Enantioselective Chan-Lam S-Arylation of Sulfenamides

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This study reports an enantioselective Chan-Lam S-arylation of sulfenamides with arylboronic acids, enabling the synthesis of valuable chiral diaryl sulfilimines previously difficult to access.

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The preprint investigates how to achieve enantioselective Chan–Lam S-arylation of sulfenamides with arylboronic acids using a copper catalyst system, combining experimental screening and mechanistic/computational analysis. Using a sulfenamide model substrate and iterative optimization of chiral ligands, base, solvent, catalyst, and additives (notably CsF) under O2 at room temperature, the authors report a protocol that produces diaryl sulfilimines bearing a sulfur stereocenter with high chemoselectivity and up to 92% ee, while improving yields. Substrate-scope experiments indicate broad functional-group tolerance (including aldehydes, ketones, esters, amides, and alcohols) and favorable S-arylation over potential competing N- or O-arylation pathways; a stated limitation is that the work is a preprint and not peer reviewed. This paper does not explicitly discuss endometriosis or adenomyosis; it was included in the corpus via a keyword match in the upstream search index.

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Abstract

Chan-Lam coupling constructs C-N, C-O and C-S bonds by coupling nucleophiles with boronic acids using copper complexes. Such methods benefit from inexpensive and sustainable catalysts, simple and mild reaction conditions, and the potential to generate products with structural diversity. However, control of the stereochemistry in this textbook transformation has proven to be a formidable challenge. We report a highly chemoselective and enantioselective Chan-Lam S -arylation of sulfenamides with arylboronic acids to deliver an array of thermodynamically disfavored diaryl sulfilimines containing a sulfur stereocenter, a class of chiral molecules of great value in chemistry and biology that were synthetically intractable previously. A combined experimental and computational study establishes the reaction mechanism and unveils the origin of chemoselectivity and stereoselectivity.
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Enantioselective Chan-Lam S-Arylation of Sulfenamides | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Enantioselective Chan-Lam S -Arylation of Sulfenamides qingjin liang, Xinping Zhang, Madeline E. Rotella, Zeyu Xu, Marisa C. Kozlowski, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2779487/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Chan-Lam coupling constructs C-N, C-O and C-S bonds by coupling nucleophiles with boronic acids using copper complexes. Such methods benefit from inexpensive and sustainable catalysts, simple and mild reaction conditions, and the potential to generate products with structural diversity. However, control of the stereochemistry in this textbook transformation has proven to be a formidable challenge. We report a highly chemoselective and enantioselective Chan-Lam S -arylation of sulfenamides with arylboronic acids to deliver an array of thermodynamically disfavored diaryl sulfilimines containing a sulfur stereocenter, a class of chiral molecules of great value in chemistry and biology that were synthetically intractable previously. A combined experimental and computational study establishes the reaction mechanism and unveils the origin of chemoselectivity and stereoselectivity. Figures Figure 1 Introduction Sulfilimines, the aza-analogues of sulfoxides, are a class of unique sulfur-stereogenic scaffolds if the two carbon-substituents are not identical. They find widespread applications in organic synthesis, serving as key intermediates 1–4 , directing groups 1–4 , nitrene transfer reagents 5 , and N -radical precursors 6 . Moreover, chiral sulfilimines have also been exploited as ligands for asymmetric transition-metal catalysis 7 . More importantly, the sulfilimine bond has been discovered to be involved in covalent crosslinks between hydroxylysine-211 and methionine-93 in collagen IV, which represents an evolutionary adaptation to mechanical stress and plays a key role in stabilizing the basement membranes of metazoa 8 . Encouraged by this striking discovery, sulfilimines have drawn increasing attention in the field of chemical biology 9–11 , and appear as a promising pharmacophore in medicinal chemistry 12 , wherein chirality at sulfur 13, 14 plays a significant role yet is long-time neglected. Despite their prevalence in chemistry and biology, synthetic methods to generate chiral sulfilimines remain underdeveloped 15 . Conventionally, enantioenriched sulfilimines are prepared by enantioselective imination of sulfides, which predominantly relies on steric differentiation of the two S -substituents by a catalyst. Following such a strategy, chiral aryl alkyl sulfilimines as well as dialkyl sulfilimines have been prepared with high optical purity, whereas very limited success has been achieved in forming enantiopure diaryl sulfilimines presumably due to the small difference in the size of the two (hetero)aryl moieties (Scheme 1A, a) 16–24 . Recently, Ellman and coworkers reported an elegant enantioselective Rh-catalyzed S -alkylation of sulfenamides with diazo compounds, representing a complimentary pathway to chiral alkyl sulfilimines (Scheme 1A, b) 25 ; however, the key rhodium carbene intermediate precludes the application of this tactic to diaryl variants. In sharp contrast to the alkyl counterparts, only two synthetic routes to diaryl sulfilimines have been disclosed to date, leveraging the stereo-induction effect of enantiopure reactants. In 1985, Oae and coworkers discovered that the in-situ formed L -menthyloxysulfonium chloride arising from the treatment of diaryl sulfides with L -menthol and t BuOCl could undergo a substitution reaction with an amine anion to produce optically active diaryl sulfilimines with low enantiomeric excess (Scheme 1A, c) 26 . Later, the Uemura group described a copper-catalyzed imination of diaryl sulfides bearing a chiral oxazolinyl moiety at the ortho -position to give the N -tosyl diaryl sulfilimines in moderate to good yields and modest to excellent diastereoselectivities (Scheme 1A, d) 27 . Therefore, a general, enantioselective method to directly prepare chiral diaryl sulfilimines with broad functional group compatibility and high levels of enantioselectivity remains an unsolved challenge. We hypothesized that this class of molecules could be assembled by an enantioselective two-component coupling strategy, such as Chan-Lam coupling, wherein a chiral catalyst would allow the effective construction of sulfur stereogenic centers possessing two very similar, or even nearly identical (hetero)aryl moieties. Chan-Lam coupling has emerged as one of the most widely practiced methods in academia and industry to construct C-N, C-O and C-S bonds over the past two decades 28, 29 , due to the mild and simple reaction conditions, inexpensive and biofriendly catalysts, among other advantages. However, no enantioselective Chan-Lam coupling has been achieved yet, as the majority of Chan − Lam protocols do not require an external ligand. Recently, our group introduced an unprecedented Chan-Lam S -arylation of sulfenamides to prepare an array of racemic diaryl sulfilimines 30 , which features unconventional chemoselectivity favoring C-S bond formation over C-N bond, broad functional group tolerance, and mild reaction conditions. The key to success for this protocol is chelation of the carbonyl group on nitrogen to the copper center, which stabilizes the substrate adduct and controls the subsequent C-S bond formation. Moreover, to prevent this highly favorable background reaction from unliganded copper, mulitdentate chiral ligands are used to favor copper coordination. This scenario limits the coordination sites available for the two requisite substrates in a Chan-Lam coupling (aryl group and sulfenamide substrate). For example, bidentate sulfenamides 30 where facial control is more easily achieved are not accommodated when such chiral ligands are employed. However, monodentate substrates need to compete with solvent molecules, anions derived from the copper source, or bases in binding to the copper center in order to effect this process. Furthermore, S -binding needs to be realized over the normally more favorable N -binding in a suitable chiral pocket. Herein, we report an enantioselective copper-catalyzed Chan-Lam coupling S -arylation of sulfenamides with arylboronic acids that overcomes these considerable challenges to provide facile access to diverse diaryl sulfilimines with high level of chemoselectivity and stereoselectivity (Scheme 1A, e). Results Reaction development. Control of the copper coordination sphere is the key to realizing ligand-controlled enantioselective Chan-Lam coupling. Reasoning, that a chelating substrate combined with a bidentate ligand would likely inhibit transmetallation from the aryl boronic acid, chelating N -groups such as acyl, carbamoyl, etc. were not employed. Rather, we strategically chose a sulfenamide bearing a phenyl group on nitrogen ( 1a ) as model substrate, along with 4- tert -butyl phenylboronic acid ( 2a ), for examination of the process. Initially, a series of privileged nitrogen-based ligands were surveyed in the presence of a copper catalyst and amine base to quench the boronic acid byproduct (Table 1 , Table S1 and Table S5). Among the chiral scaffolds tested, 2-pyridyl oxazolidine ligand L4 outperformed by delivering the desired product 3aa in 43% ee (Table 1 , entry 4). Further optimization of the other parameters with this ligand (see Table S2-4) revealed that i Pr 2 NEt (2.0 equiv) as base, dimethoxyethane (DME) as solvent, and copper(I) thiophene-2-carboxylate (CuTc, 10 mol %) as catalysts improved the outcome forming 3aa with 50% yield and 58% ee (entry 5). Perturbing the ligand to a slightly nonplanar geometry by incorporation of an aryl group in L5 (entry 6) improved the assay yield (60%) and enantiomeric excess (71%) of 3aa . Permutation of this substitution to the imidazole moiety ( L6 ) leads to superior enantiocontrol (80% ee) albeit with slightly diminished assay yield (44%, entry 7). Installation of a further ortho -fluoro group on the pyridine ( L7) led to much lower yield and ee values (entry 8). Consequently, further modification of the ligands focused on the imidazole portion. At this juncture, addition of CsF (50 mol %) was examined to enhance turnover by activation of the boronic acid 31 . In line with this hypothesis, the yield was doubled while retaining the same enantioselectivity (entry 9 vs entry 7). As such, was CsF employed in all further trials. Addition of an ethyl group to the 5-poistion of the imidazole ring would further constrain the geometry and shift the t Bu closer to bound substrates. Indeed, this perturbation resulted in excellent catalytic activity (85–86% assay yield) with the trans disposition in L9 giving the higher enantioselectivity (90% ee; compare entry 11 with 10). Further increasing the steric effect from the 5-position by employing a benzyl group in place of the ethyl group ( L10 ) resulted in improved enantioselectivity (92% ee) while maintaining the high efficiency of the transformation. Ultimately, adjusting the base from i Pr 2 NEt to Na 2 CO 3 afforded 3aa in 88% assay yield, 83% isolated yield, with 92% ee (entry 11). Thus, the optimal conditions for enantioselective Chan-Lam coupling of sulfenamide were determined to be: 1a as limiting reagent, 2a (2.0 equiv) as coupling partner, CuTc (10 mol %)/ L10 (15 mol %) as catalyst system, Na 2 CO 3 (2.0 equiv) as base, CsF (50 mol %) as additive, in DME under an O 2 atmosphere at room temperature for 12 h. For a complete list of optimization conditions, see Tables S1-9 in SI for details. Substrate Scope. With the optimal conditions established, we examined the generality of this enantioselective Chan-Lam coupling reaction (Table 2 ). The larger naphthalene substrate ( 1b ) was similarly effective and a crystal structure thereof permitted unambiguous assignment of the absolute ( S )-configuration (see Table S10-16 for details); the configurations of the other products in Table 2 were assigned by analogy. Electron-donating 4-OMe ( 1c ) and 4-Me ( 1d ) or electron-withdrawing 4-F ( 1a ), 4-Cl ( 1e ), 4-Br ( 1f ), 4-CO 2 Et ( 1g ), 4-CF 3 ( 1h ), 4-CN ( 1i ), and 4-NO 2 ( 1j ) aryl groups on the sulfur of the sulfenamide were all well tolerated furnishing the corresponding products in good yields with excellent enantiocontrol. Attesting to the mild conditions, various functional groups, such as aldehyde ( 1k ), ketone ( 1l ), ester ( 1g ), amide ( 1m ) and alcohol ( 1n ) were all compatible under the optimal conditions, providing the products in 61 − 72% yields and 81 − 91% ee. Remarkably, this enantioselective Chan-Lam coupling protocol displayed excellent chemoselectivity favoring S -arylation of sulfenamide ( 1a ) over other functional groups that typically undergo Chan-Lam coupling such as the amide N-H ( 1m ) or alcohol O-H ( 1n ), highlighting the unique nature of this protocol. The chemistry was well-accommodated with sulfenamides bearing meta -substituted aryl groups, as evidenced by the formation of 3oa and 3pa in 67% with 89% ee and 73% with 88% ee, respectively. Moreover, the newly devised method proceeded smoothly with challenging S -heterocyclic sulfenamides allowing an array of chiral S -heteroaryl sulfilimines, including pyridyl ( 3qa , 3ra ), quinolinyl ( 3sa ), and thienyl ( 3ta , 3ua ) to be obtained with good enantioselectivities (70–88% ee), albeit in modest yields (45 − 75%). Next, the N -aryl substitution of the sulfenamides was examined. Both electron-donating ( 1v ) and electron-withdrawing aryls ( 1w , 1x, 1y ) gave the desired products ( 3va - ya ) with 60–84% yields and 83–94% enantioselectivity. Importantly, a set of functional groups, including aldehyde ( 1z ), ketone ( 1aa ), ester ( 1y ), and even the polymerizable vinyl group ( 1ab ), were well tolerated in the protocol to deliver the corresponding chiral diaryl sulfilimines ( 3ya - aba ) in good yields (77 − 89%) with good to excellent enantiocontrol (74 − 93% ee). These results highlight the advantages of this protocol as the aldehyde and terminal alkene are not tolerated in the previously reported route, oxidative imination of sulfides, due to the competing oxidation. Sterically hindered N -(2-Br-phenyl) sulfenamide ( 1ac ) reacted with 2a under the optimal conditions to afford 3aca in 74% with 84% ee. meta -Substituted N -aryl sulfenamides, including 3-methoxy ( 1ad ), 3-iodo ( 1ae ), and 3-acetamido ( 1af ), were competent coupling partners to deliver sulfilimines 3ada - fa in 71 − 81% yields with 74 − 91% ee. Heteroaromatic sulfenamides, such as pyridines 1ag , 1ah and pyrimidine 1ai , also proved to be potent coupling partners to furnish chiral N -heterocyclic diaryl sulfilimines 3aga - ia in satisfactory yields with good stereocontrol. The use of alternate arylboronic acids was next interrogated. The 2-naphthalene ( 2b ) variant again proved effective at this position. Electron-donating substrates including 4-OBn ( 2c ), 4- n butyl ( 2d ), 4-TMS ( 2e ), 4-PhO ( 2f ), and 4-Ph ( 2g ) and electron-neutral substrates 4-MeS ( 2h ) and 4-H ( 2i ) furnished the products 3ab - i in moderate to good yields while sustaining good stereoselectivities. In particular, 3ah is synthetically intractable via the classic imination of sulfides, since it contains two functionalities with different oxidation states of sulfur. Importantly, labile trimethylsilyl ( 2e ) or vinyl ( 1j ) groups were also amendable to the chemistry, providing a means for later modification via other orthogonal processes. Moreover, meta -substituted arylboronic acids ( 2k - m ) were effective. Finally, the heterocyclic benzofuranyl boronic acid ( 2n ) generated 3an with good selectivity (87% ee). Synthetic Utility. A major source of nitrogen-based chiral ligands is inexpensive and abundant natural L -amino acids, which, in turn, limits the availability of the enantiomeric congeners. In this instance, the opposite enantiomeric ligand of L10 is derived from an expensive D -amino acid. Thus, generation of both of enantiomeric products from the same, less expensive chiral ligand would be a distinct advantage. Simply exchanging the aryl groups of the sulfenamide and arylboronic acid substrates enabled such an outcome. Thus, synthesis of both enantiomers of sulfilimine 3dl was achieved by using 1d with 2l vs 1o with 2o under the identical catalytic conditions (Scheme 2a ). In addition, the chiral S(IV)-based sulfilimines obtained by our enantioselective Chan-Lam S -alkylation could serve as versatile intermediates to access to chiral S(VI)-based sulfoximines. Exposure of sulfilimine 3va to NaClO leads to the formation of sulfoximine 4a with no detectable erosion of enantiomeric excess at the sulfur stereocenter 32 (Scheme 2b ). Next, we showed the synthetic utility of this method due to the emerging role of sulfilimines in medicinal chemistry. Inspired by the elaboration of pan-CDK inhibitor Bay1000394 from Bayer by switching the sulfonamide to a sulfoximine as the pharmocophore 33 , two sulfilimine analogues of patented bioactive molecules were generated using our enantioselective Chan-Lam coupling as the key step (Scheme 2c ). Sulfilimine 9 , an analog of an agonist ( 9’ ) of AMP-activated protein kinase (AMPK) in the treatment of degenerative neurological diseases 34 , could be synthesized in three steps with 60% overall yield and 80% ee. Compound 14 , an analog of the sulfoxide-based histone-lysine N -methyltransferase EZH2 Inhibitor ( 14’ ) 35 , was concisely assembled in four steps with a 28% yield and 86% ee. Remarkably, compound 12 bearing a labile activated ester group reacted efficiently with 2a to deliver the corresponding chiral sulfilimine in good stereoselectivity, underlining the broad functional group compatibility. Overall, the method described herein offers a versatile platform to afford a range of derivatives in a step-economic manner. Mechanistic Studies. To understand the factors controlling chemo- and enantioselectivity, the mechanism was probed using density functional theory (DFT) [UM06/6-311 + + G(d,p)-SDD(Cu)-CPCM(DME)//UB3LYP-D3/6-31G(d)-SDD(Cu) 36–44 , see Supporting Information for full computational details]. Initially, Cu II complex 1’ forms the pre-reacting complex 1 with the incoming aryl boronic acid (Fig. 1 a, downhill in energy by 2.0 kcal/mol). This complex then undergoes transmetalation (via [ 1 – 2 ], 3.9 kcal/mol) to form intermediate 2 (−25.1 kcal/mol) following dissociation of boric acid. Next, sulfenamide coordinates to 2 to form 2a’ (−20.6 kcal/mol). Intermediate 2a’ can undergo kinetically controlled S -arylation (Fig. 1 b, blue pathway) or the higher energy N -arylation (Fig. 1 b, red pathway). For the S -arylation, Cu II intermediate 2a’ first undergoes disproportionation with Cu II intermediate 1’ to form Cu III complex 2’ (Fig. 1 b, blue, −22.4 kcal/mol) and LCu I hydroxide. Thiophene carboxylate dissociates from the inner coordination sphere of the Cu III complex to form the square pyramidal Cu III cationic complex 2c’ . Cystallographic evidence of various square pyramidal cationic Cu III species supports the formation of such an intermediate 45 . Furthermore, the imidazole ring of L2 , a strong sigma donor, is trans to sulfur, (see Figure S1). Next, sulfur-arylation occurs via [ 2 – 3 ] (overall energetic span 46 of 8.0 kcal/mol from intermediate 2a’ ) to give protonated S -arylation product 3’-S . Finally, deprotonation of the nitrogen atom gives the final product 3-S . To understand the chemoselectivity observed in this transformation, we also computed the formation of the N -aryl product (Fig. 1 b, red). From intermediate 2a’ , deprotonation must occur prior to N -arylation in order for the nitrogen atom to react (for a comparison of energetic spans of N -arylation before and after deprotonation, see Figure S2). The nitrogen atom of the sulfenamide undergoes deprotonation with NMe 3 as the base (as a simplified model for i Pr 2 NEt) via 2’-TS (overall energetic span of 14.0 kcal/mol) to form intermediate 2d’ . Disproportionation of Cu II species 2d’ with Cu II intermediate 1’ yields Cu III intermediate 2b’ and LCu I hydroxide. From intermediate 2b’ , N -arylation occurs via [2’-4] , giving the thermodynamically favored product 4 . Notably, S -arylation is under kinetic control as the energetic span to form the product 3’-S is lower by 6.0 kcal/mol, explaining the observed experimental chemoselectivity in this transformation. This kinetic control overcomes the far greater stability of the N -aryl product relative to the S -aryl product 30 . Next, we delved further into the chemoselectivity by comparing the experimental results with different ligands to our computational results (see Figures S3-4 in the Supporting Information). Notably, ligand L47 , which gives a greater amount of N -arylation product, has a smaller difference between energy spans for S -arylation and N -arylation (see Table S17). This agreement of the experimental results with our computational findings provides additional support for the proposed mechanism. Finally, the origin of enantioselectivity in this transformation was investigated. The lowest energy conformations of the S -arylation transition state leading to ( S )-enantiomer and ( R )-enantiomer are shown in Fig. 1 c (for comparison of energetics with different methods, see Tables S18-20). Upon initial inspection of the transition state geometries, it is unclear what factors control the excellent enantioselectivity observed in this transformation (see Figure S5). As a result, interaction/distortion analysis was performed as described by Houk and Bickelhaupt 47 (see Figure S6) in which the favorable interaction energy between the copper-ligand (CuL) and aryl substrate is compared with the energy required to distort the intermediates into the transition state geometries. The distortion in the LCu component of [ 2 – 3 ] R is 27.2 kcal/mol, which is much greater than the analogous distortion in the [ 2 – 3 ] S (12.0 kcal/mol). This distortion in the LCu component can be observed in the overlaid transition state and intermediate geometries given in Figure S7. However, the interaction energy between the two LCu and aryl substrate components is greater in [ 2 – 3 ] R , giving an overall energy of −34.4 kcal/mol compared to −34.1 kcal/mol in [ 2 – 3 ] S . Based on this analysis, the observed enantioselectivity does not arise predominantly from a difference in interaction energy. Rather, the difference in distortion need to accommodate the two transition states drives the enantioselectivity. Thus, the difference in free energy between [ 2 – 3 ] R and [ 2 – 3 ] S was further explored. Since [ 2 – 3 ] S is favored by 2.9 kcal/mol in free energy, but only by 0.3 kcal/mol in enthalpy, we attributed the enantioselectivity to this free energy difference. On further examination of the transition state geometries (Fig. 1 c), the S -arylation leading to the ( S )-enantiomer has an 8-membered ring involved in the bond formation whereas [ 2 – 3 ] R has a 6-membered ring. Since the 8-membered ring is more flexible, it is more entropically favored, which results in a favorable free energy for [ 2 – 3 ] S. Finally, the decrease in the observed experimental enantioselectivity when the substrate is changed from the unsubstituted phenyl substrate (left, Figure S7) to the p -NO 2 substituted substrate (right, Figure S7) was computed with L10 ligand. In agreement with the observed experimental decrease in enantioselectivity (from 92% ee to 56% ee), the free energy difference also decreases (from 2.9 kcal/mol to 0.7 kcal/mol). Conclusion In summary, we have introduced a highly chemoselective and enantioselective Chan-Lam coupling of sulfenamides with arylboronic acids to synthesize a diverse range of diaryl sulfilimines containing a stereogenic sulfur center. A copper catalyst generated from the newly developed 2-pyridyl N -phenyl imidazole ligand enables effective enantiocontrol by means of a well-defined chiral environment and high reactivity that outcompetes the background racemic transformation. With this strategy, a single chiral ligand can deliver either enantiomeric product by exchanging the aryl groups of the sulfenamide and arylboronic acid substrates, thereby circumventing the need to prepare the enantiomeric ligands from the unnatural D -amino acids. In addition, the synthetic utility of this unprecedented asymmetric coupling was underscored by synthesis of two sulfilimine-analogs of patented bioactive molecules. In concert with experimental data, computational studies reveal the unconventional chemoselectivity favoring C-S bond over C-N bond was enabled by disproportionation of Cu(II) complexes prior to deprotonation of sulfenamides. Furthermore, the excellent enantioselectivity arises from the difference of entropy between the transition states. The protocol described herein represents the first enantioselective Chan-Lam coupling, which is anticipated to serve as a powerful tool to prepare chiral scaffolds in medicinal chemistry and organic synthesis. Methods General Procedure for Catalysis. To an oven-dried microwave vial equipped with a stir bar was added sulfenamide 1 (0.10 mmol), arylboronic acid 2 (0.2 mmol, 2.0 equiv), CuTc (1.9 mg, 0.01 mmol), L10 (5.5 mg, 0.015 mmol), CsF (7.6 mg, 0.05 mmol), and Na 2 CO 3 (21.2 mg, 0.2 mmol). Then, the microwave vial was sealed with a cap. Oxygen was purged/vacuumed three times through a three-way valve, and the microwave tube turned to an oxygen atmosphere. DME (1.0 mL) was added into the reaction vial via syringe, and the reaction solution was stirred at room temperature under the oxygen atmosphere for 12 h. Upon completion of the reaction, the vial was opened to air, and the solution was concentrated under reduced pressure. The crude product was purified by flash chromatography, as outlined below, to afford the pure product. Declarations Data availability Detailed experimental procedures, characterization data, NMR spectra of new compounds, detailed computational study, and calculated structures are available within Supplementary Information. Any further relevant data are available from the authors upon reasonable request. CCDC 2215359 (3ba) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected] , or by contacting The Cambridge Crystal-lographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033. ACKNOWLEDGMENTS T.J. thanks Guangdong-Joint Foundation of Shenzhen (2021B1515120046, 2022B1515120075), Natural Science Foundation of Guangdong Province (2022A1515011770), and the Science and Technology Innovation Commission of Shenzhen Municipality (JCYJ20220818101404010, 20220815113214003) for financial support. M.C.K. thanks the NIH (R35 GM131902) for financial support and XSEDE (TG-CHE120052) for computational support. We are very grateful to Dr. Yang Yu and Dr. Xiaoyong Chang (both at SUSTech) for HRMS and X-ray crystallography respectively. We acknowledge the assistance of SUSTech Core Research Facilities. Author contributions T.J. conceived and supervised the project. Q.L., X.Z. and Z.X. performed the experiments. M.C.K. directed the part of computational study. M.E.R. carried out computational study. T.J., Q.L. and X.Z. analyzed the data. All authors participated in writing the manuscript. Q.L., X.Z. and M.E.R. contributed equally. Competing interests The authors declare no competing interests. Additional information Supplementary information is available for this paper. Correspondence and requests for materials should be addressed to T.J. References Gilchrist, T.L. & Moody, C.J. The Chemistry of Sulfilimines. Chem. Rev. 77 , 409-435 (1977). Furukawa, N. & Oae, S. Sulfilimines. 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Petersson, G.A. & Al‐Laham, M.A. A Complete Basis Set Model Chemistry. II. Open‐Shell Systems and the Total Energies of the First‐Row Atoms. J. Chem. Phys. 94 , 6081-6090 (1991). Andrae, D., Häußermann, U., Dolg, M., Stoll, H. & Preuß, H. Energy-Adjusted ab Initio Pseudopotentials for the Second and Third Row Transition Elements. Theor. Chim. Acta. 77 , 123-141 (1990). Zhao, Y. & Truhlar, D.G. The M06 Suite of Density Functionals for Main Group Thermochemistry, Thermochemical Kinetics, Noncovalent Interactions, Excited States, and Transition Elements: Two New Functionals and Systematic Testing of Four M06-Class Functionals and 12 Other Functionals. Theor. Chem. Acc. 120 , 215-241 (2008). McLean, A.D. & Chandler, G.S. Contracted Gaussian Basis Sets for Molecular Calculations. I. Second Row Atoms, Z=11–18. J. Chem. Phys. 72 , 5639-5648 (1980). Krishnan, R., Binkley, J.S., Seeger, R. & Pople, J.A. Self‐Consistent Molecular Orbital Methods. XX. A Basis Set for Correlated Wave Functions. 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Tables Tables 1 and 2 are available in the Supplementary Files section. Schemes Schemes 1 and 2 are available in the Supplemental Files section. Supplementary Information The Supplementary Information files are not available with this version. Supplementary Files Scheme1.jpg Scheme 1. Approaches to Enantioenriched Sulfilimines; Conceptual Design and Major Challenges Scheme2.jpg Scheme 2. Synthetic Applications Tables.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2779487","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":189297573,"identity":"b2b6e250-dd09-445b-880e-a96b81131903","order_by":0,"name":"qingjin liang","email":"","orcid":"","institution":"southern university of science and technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"qingjin","middleName":"","lastName":"liang","suffix":""},{"id":189297574,"identity":"c7f1531d-0f3f-488d-900c-f2ec86c2beec","order_by":1,"name":"Xinping Zhang","email":"","orcid":"","institution":"southern university of science and technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Xinping","middleName":"","lastName":"Zhang","suffix":""},{"id":189297575,"identity":"e132bbba-8e30-4e86-bb64-38ffb07403b4","order_by":2,"name":"Madeline E. Rotella","email":"","orcid":"","institution":"University of Pennsylvania","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Madeline","middleName":"E.","lastName":"Rotella","suffix":""},{"id":189297576,"identity":"9c95d7f0-c01e-4735-8a15-32f6bf55be93","order_by":3,"name":"Zeyu Xu","email":"","orcid":"","institution":"southern university of science and technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zeyu","middleName":"","lastName":"Xu","suffix":""},{"id":189297577,"identity":"d2d4bb1a-77f1-4733-b19a-9ac13d238248","order_by":4,"name":"Marisa C. Kozlowski","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYJCCAwwMNigCBsRoSSNRCxAcJkGLbvvZhwd/1Jy35+8/wCZdUHEnj4G9eZsEPi1mZ9INDvMcu50440YCm/SMM8+KGXiOleHXciAN6Cq22wkMNxjYpHnbDic2SOSY4ddy/hnDwR//ztnLnwc6jPcfUIv8GwJabqQxHOBtO8C44QDQYbwNIFt4CGl5xnCYty85ceONxGbrGccOJ7bxpBVb4HdYGvPHH9/s7OXOHz54u6DmcGI/++GNN/BpQQKMDcwgio1I5RDATJLqUTAKRsEoGDEAAMS3TBgwFE3fAAAAAElFTkSuQmCC","orcid":"","institution":"University of Pennsylvania","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Marisa","middleName":"C.","lastName":"Kozlowski","suffix":""},{"id":189297578,"identity":"7058cf29-81d2-4301-9119-e6d1e6195393","order_by":5,"name":"Tiezheng Jia","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYBACxmYQWQHhMIMEGojQAlR0BshiI1YLWBFjGylamNuZnz/8Oa8ucf785oOfCxhsZDccYH72AL/D2AwbJLcdTtxwjC1ZegZDmvGGA2zmBgT8YthguO1A4gY2HjNmHgag3gM8bBL4tbB/bEicA3RYG/83oJb/xGjhMWw42MCc2HCMhw2o5QBRWgpnNhw7bLzhWJqxNI9BsvHMw2xmeLUY9h/f8PFHTZ3s/ObDDz/zVNjJ9h1vfoZfSwMKFxRUzPjUA4E8AflRMApGwSgYBQwMAEKLRyWy7i+fAAAAAElFTkSuQmCC","orcid":"","institution":"southern university of science and technology","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Tiezheng","middleName":"","lastName":"Jia","suffix":""}],"badges":[],"createdAt":"2023-04-05 07:01:35","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2779487/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2779487/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":35418904,"identity":"d29c54fc-0de4-44ea-b22b-6a6bf66805b3","added_by":"auto","created_at":"2023-04-06 21:35:22","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":761683,"visible":true,"origin":"","legend":"\u003cp\u003ea) Formation of common intermediate \u003cstrong\u003e2a’\u003c/strong\u003e, which can undergo \u003cem\u003eN\u003c/em\u003e-arylation or \u003cem\u003eS\u003c/em\u003e-arylation. b) Formation of \u003cem\u003eS\u003c/em\u003e-arylation product \u003cstrong\u003e3-S\u003c/strong\u003e via kinetic control. c) Formation of (\u003cem\u003eS\u003c/em\u003e)-product over (\u003cem\u003eR\u003c/em\u003e)-product, an entropically controlled process. All free energies were computed using UM06/6-311++G(d,p)-SDD(Cu)-CPCM(DME)//UB3LYP-D3/6-31G(d)-SDD(Cu).\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2779487/v1/0b81dcea15c13f4b6f8f87f7.jpg"},{"id":35418906,"identity":"ae166420-8595-4c81-a92b-110cee59cde0","added_by":"auto","created_at":"2023-04-06 21:35:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":562463,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2779487/v1/f3dc60d2-f59e-4be1-9395-0863b9a842dc.pdf"},{"id":35418902,"identity":"1fe57f76-4d3b-475a-bece-6e2c38b4183e","added_by":"auto","created_at":"2023-04-06 21:35:22","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":462754,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme 1.\u003c/strong\u003e \u003cstrong\u003eApproaches to Enantioenriched Sulfilimines\u003c/strong\u003e; \u003cstrong\u003eConceptual Design and Major Challenges\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Scheme1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2779487/v1/885165de8280bc96d387f74f.jpg"},{"id":35418905,"identity":"c5d8c063-b138-40d6-8199-6904f929bca6","added_by":"auto","created_at":"2023-04-06 21:35:22","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":520134,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme 2. Synthetic Applications\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Scheme2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2779487/v1/7a64d8697eb4626c4f130b1b.jpg"},{"id":35418903,"identity":"abcd6ae2-20d2-461d-b71b-0a56646c97a5","added_by":"auto","created_at":"2023-04-06 21:35:22","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":2182145,"visible":true,"origin":"","legend":"","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-2779487/v1/187957c379b1ed73e3ba9aad.docx"}],"financialInterests":"","formattedTitle":"\u003cp\u003e\u003cstrong\u003eEnantioselective Chan-Lam \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eS\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e-Arylation of Sulfenamides\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSulfilimines, the aza-analogues of sulfoxides, are a class of unique sulfur-stereogenic scaffolds if the two carbon-substituents are not identical. They find widespread applications in organic synthesis, serving as key intermediates\u003csup\u003e1\u0026ndash;4\u003c/sup\u003e, directing groups\u003csup\u003e1\u0026ndash;4\u003c/sup\u003e, nitrene transfer reagents\u003csup\u003e5\u003c/sup\u003e, and \u003cem\u003eN\u003c/em\u003e-radical precursors\u003csup\u003e6\u003c/sup\u003e. Moreover, chiral sulfilimines have also been exploited as ligands for asymmetric transition-metal catalysis\u003csup\u003e7\u003c/sup\u003e. More importantly, the sulfilimine bond has been discovered to be involved in covalent crosslinks between hydroxylysine-211 and methionine-93 in collagen IV, which represents an evolutionary adaptation to mechanical stress and plays a key role in stabilizing the basement membranes of metazoa\u003csup\u003e8\u003c/sup\u003e. Encouraged by this striking discovery, sulfilimines have drawn increasing attention in the field of chemical biology\u003csup\u003e9\u0026ndash;11\u003c/sup\u003e, and appear as a promising pharmacophore in medicinal chemistry\u003csup\u003e12\u003c/sup\u003e, wherein chirality at sulfur\u003csup\u003e13, 14\u003c/sup\u003e plays a significant role yet is long-time neglected.\u003c/p\u003e\n\u003cp\u003eDespite their prevalence in chemistry and biology, synthetic methods to generate chiral sulfilimines remain underdeveloped\u003csup\u003e15\u003c/sup\u003e. Conventionally, enantioenriched sulfilimines are prepared by enantioselective imination of sulfides, which predominantly relies on steric differentiation of the two \u003cem\u003eS\u003c/em\u003e-substituents by a catalyst. Following such a strategy, chiral aryl alkyl sulfilimines as well as dialkyl sulfilimines have been prepared with high optical purity, whereas very limited success has been achieved in forming enantiopure diaryl sulfilimines presumably due to the small difference in the size of the two (hetero)aryl moieties (Scheme 1A, a)\u003csup\u003e16\u0026ndash;24\u003c/sup\u003e. Recently, Ellman and coworkers reported an elegant enantioselective Rh-catalyzed \u003cem\u003eS\u003c/em\u003e-alkylation of sulfenamides with diazo compounds, representing a complimentary pathway to chiral alkyl sulfilimines (Scheme 1A, b)\u003csup\u003e25\u003c/sup\u003e; however, the key rhodium carbene intermediate precludes the application of this tactic to diaryl variants. In sharp contrast to the alkyl counterparts, only two synthetic routes to diaryl sulfilimines have been disclosed to date, leveraging the stereo-induction effect of enantiopure reactants. In 1985, Oae and coworkers discovered that the \u003cem\u003ein-situ\u003c/em\u003e formed \u003cem\u003eL\u003c/em\u003e-menthyloxysulfonium chloride arising from the treatment of diaryl sulfides with \u003cem\u003eL\u003c/em\u003e-menthol and \u003csup\u003e\u003cem\u003et\u003c/em\u003e\u003c/sup\u003eBuOCl could undergo a substitution reaction with an amine anion to produce optically active diaryl sulfilimines with low enantiomeric excess (Scheme 1A, c)\u003csup\u003e26\u003c/sup\u003e. Later, the Uemura group described a copper-catalyzed imination of diaryl sulfides bearing a chiral oxazolinyl moiety at the \u003cem\u003eortho\u003c/em\u003e-position to give the \u003cem\u003eN\u003c/em\u003e-tosyl diaryl sulfilimines in moderate to good yields and modest to excellent diastereoselectivities (Scheme 1A, d)\u003csup\u003e27\u003c/sup\u003e. Therefore, a general, enantioselective method to directly prepare chiral diaryl sulfilimines with broad functional group compatibility and high levels of enantioselectivity remains an unsolved challenge.\u003c/p\u003e\n\u003cp\u003eWe hypothesized that this class of molecules could be assembled by an enantioselective two-component coupling strategy, such as Chan-Lam coupling, wherein a chiral catalyst would allow the effective construction of sulfur stereogenic centers possessing two very similar, or even nearly identical (hetero)aryl moieties. Chan-Lam coupling has emerged as one of the most widely practiced methods in academia and industry to construct C-N, C-O and C-S bonds over the past two decades\u003csup\u003e28, 29\u003c/sup\u003e, due to the mild and simple reaction conditions, inexpensive and biofriendly catalysts, among other advantages. However, no enantioselective Chan-Lam coupling has been achieved yet, as the majority of Chan\u0026thinsp;\u0026minus;\u0026thinsp;Lam protocols do not require an external ligand. Recently, our group introduced an unprecedented Chan-Lam \u003cem\u003eS\u003c/em\u003e-arylation of sulfenamides to prepare an array of racemic diaryl sulfilimines\u003csup\u003e30\u003c/sup\u003e, which features unconventional chemoselectivity favoring C-S bond formation over C-N bond, broad functional group tolerance, and mild reaction conditions. The key to success for this protocol is chelation of the carbonyl group on nitrogen to the copper center, which stabilizes the substrate adduct and controls the subsequent C-S bond formation. Moreover, to prevent this highly favorable background reaction from unliganded copper, mulitdentate chiral ligands are used to favor copper coordination. This scenario limits the coordination sites available for the two requisite substrates in a Chan-Lam coupling (aryl group and sulfenamide substrate). For example, bidentate sulfenamides\u003csup\u003e30\u003c/sup\u003e where facial control is more easily achieved are not accommodated when such chiral ligands are employed. However, monodentate substrates need to compete with solvent molecules, anions derived from the copper source, or bases in binding to the copper center in order to effect this process. Furthermore, \u003cem\u003eS\u003c/em\u003e-binding needs to be realized over the normally more favorable \u003cem\u003eN\u003c/em\u003e-binding in a suitable chiral pocket. Herein, we report an enantioselective copper-catalyzed Chan-Lam coupling \u003cem\u003eS\u003c/em\u003e-arylation of sulfenamides with arylboronic acids that overcomes these considerable challenges to provide facile access to diverse diaryl sulfilimines with high level of chemoselectivity and stereoselectivity (Scheme 1A, e).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eReaction development.\u003c/strong\u003e Control of the copper coordination sphere is the key to realizing ligand-controlled enantioselective Chan-Lam coupling. Reasoning, that a chelating substrate combined with a bidentate ligand would likely inhibit transmetallation from the aryl boronic acid, chelating \u003cem\u003eN\u003c/em\u003e-groups such as acyl, carbamoyl, etc. were not employed. Rather, we strategically chose a sulfenamide bearing a phenyl group on nitrogen (\u003cstrong\u003e1a\u003c/strong\u003e) as model substrate, along with 4-\u003cem\u003etert\u003c/em\u003e-butyl phenylboronic acid (\u003cstrong\u003e2a\u003c/strong\u003e), for examination of the process. Initially, a series of privileged nitrogen-based ligands were surveyed in the presence of a copper catalyst and amine base to quench the boronic acid byproduct (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, Table S1 and Table S5). Among the chiral scaffolds tested, 2-pyridyl oxazolidine ligand \u003cstrong\u003eL4\u003c/strong\u003e outperformed by delivering the desired product \u003cstrong\u003e3aa\u003c/strong\u003e in 43% ee (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, entry 4). Further optimization of the other parameters with this ligand (see Table S2-4) revealed that \u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003ePr\u003csub\u003e2\u003c/sub\u003eNEt (2.0 equiv) as base, dimethoxyethane (DME) as solvent, and copper(I) thiophene-2-carboxylate (CuTc, 10 mol %) as catalysts improved the outcome forming \u003cstrong\u003e3aa\u003c/strong\u003e with 50% yield and 58% ee (entry 5). Perturbing the ligand to a slightly nonplanar geometry by incorporation of an aryl group in \u003cstrong\u003eL5\u003c/strong\u003e (entry 6) improved the assay yield (60%) and enantiomeric excess (71%) of \u003cstrong\u003e3aa\u003c/strong\u003e. Permutation of this substitution to the imidazole moiety (\u003cstrong\u003eL6\u003c/strong\u003e) leads to superior enantiocontrol (80% ee) albeit with slightly diminished assay yield (44%, entry 7). Installation of a further \u003cem\u003eortho\u003c/em\u003e-fluoro group on the pyridine (\u003cstrong\u003eL7)\u003c/strong\u003e led to much lower yield and ee values (entry 8). Consequently, further modification of the ligands focused on the imidazole portion. At this juncture, addition of CsF (50 mol %) was examined to enhance turnover by activation of the boronic acid\u003csup\u003e31\u003c/sup\u003e. In line with this hypothesis, the yield was doubled while retaining the same enantioselectivity (entry 9 vs entry 7). As such, was CsF employed in all further trials. Addition of an ethyl group to the 5-poistion of the imidazole ring would further constrain the geometry and shift the \u003csup\u003e\u003cem\u003et\u003c/em\u003e\u003c/sup\u003eBu closer to bound substrates. Indeed, this perturbation resulted in excellent catalytic activity (85\u0026ndash;86% assay yield) with the \u003cem\u003etrans\u003c/em\u003e disposition in \u003cstrong\u003eL9\u003c/strong\u003e giving the higher enantioselectivity (90% ee; compare entry 11 with 10). Further increasing the steric effect from the 5-position by employing a benzyl group in place of the ethyl group (\u003cstrong\u003eL10\u003c/strong\u003e) resulted in improved enantioselectivity (92% ee) while maintaining the high efficiency of the transformation. Ultimately, adjusting the base from \u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003ePr\u003csub\u003e2\u003c/sub\u003eNEt to Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e afforded \u003cstrong\u003e3aa\u003c/strong\u003e in 88% assay yield, 83% isolated yield, with 92% ee (entry 11). Thus, the optimal conditions for enantioselective Chan-Lam coupling of sulfenamide were determined to be: \u003cstrong\u003e1a\u003c/strong\u003e as limiting reagent, \u003cstrong\u003e2a\u003c/strong\u003e (2.0 equiv) as coupling partner, CuTc (10 mol %)/\u003cstrong\u003eL10\u003c/strong\u003e (15 mol %) as catalyst system, Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e (2.0 equiv) as base, CsF (50 mol %) as additive, in DME under an O\u003csub\u003e2\u003c/sub\u003e atmosphere at room temperature for 12 h. For a complete list of optimization conditions, see Tables S1-9 in SI for details.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSubstrate Scope.\u003c/strong\u003e With the optimal conditions established, we examined the generality of this enantioselective Chan-Lam coupling reaction (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The larger naphthalene substrate (\u003cstrong\u003e1b\u003c/strong\u003e) was similarly effective and a crystal structure thereof permitted unambiguous assignment of the absolute (\u003cem\u003eS\u003c/em\u003e)-configuration (see Table S10-16 for details); the configurations of the other products in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e were assigned by analogy. Electron-donating 4-OMe (\u003cstrong\u003e1c\u003c/strong\u003e) and 4-Me (\u003cstrong\u003e1d\u003c/strong\u003e) or electron-withdrawing 4-F (\u003cstrong\u003e1a\u003c/strong\u003e), 4-Cl (\u003cstrong\u003e1e\u003c/strong\u003e), 4-Br (\u003cstrong\u003e1f\u003c/strong\u003e), 4-CO\u003csub\u003e2\u003c/sub\u003eEt (\u003cstrong\u003e1g\u003c/strong\u003e), 4-CF\u003csub\u003e3\u003c/sub\u003e (\u003cstrong\u003e1h\u003c/strong\u003e), 4-CN (\u003cstrong\u003e1i\u003c/strong\u003e), and 4-NO\u003csub\u003e2\u003c/sub\u003e (\u003cstrong\u003e1j\u003c/strong\u003e) aryl groups on the sulfur of the sulfenamide were all well tolerated furnishing the corresponding products in good yields with excellent enantiocontrol. Attesting to the mild conditions, various functional groups, such as aldehyde (\u003cstrong\u003e1k\u003c/strong\u003e), ketone (\u003cstrong\u003e1l\u003c/strong\u003e), ester (\u003cstrong\u003e1g\u003c/strong\u003e), amide (\u003cstrong\u003e1m\u003c/strong\u003e) and alcohol (\u003cstrong\u003e1n\u003c/strong\u003e) were all compatible under the optimal conditions, providing the products in 61\u0026thinsp;\u0026minus;\u0026thinsp;72% yields and 81\u0026thinsp;\u0026minus;\u0026thinsp;91% ee. Remarkably, this enantioselective Chan-Lam coupling protocol displayed excellent chemoselectivity favoring \u003cem\u003eS\u003c/em\u003e-arylation of sulfenamide (\u003cstrong\u003e1a\u003c/strong\u003e) over other functional groups that typically undergo Chan-Lam coupling such as the amide N-H (\u003cstrong\u003e1m\u003c/strong\u003e) or alcohol O-H (\u003cstrong\u003e1n\u003c/strong\u003e), highlighting the unique nature of this protocol. The chemistry was well-accommodated with sulfenamides bearing \u003cem\u003emeta\u003c/em\u003e-substituted aryl groups, as evidenced by the formation of \u003cstrong\u003e3oa\u003c/strong\u003e and \u003cstrong\u003e3pa\u003c/strong\u003e in 67% with 89% ee and 73% with 88% ee, respectively. Moreover, the newly devised method proceeded smoothly with challenging \u003cem\u003eS\u003c/em\u003e-heterocyclic sulfenamides allowing an array of chiral \u003cem\u003eS\u003c/em\u003e-heteroaryl sulfilimines, including pyridyl (\u003cstrong\u003e3qa\u003c/strong\u003e, \u003cstrong\u003e3ra\u003c/strong\u003e), quinolinyl (\u003cstrong\u003e3sa\u003c/strong\u003e), and thienyl (\u003cstrong\u003e3ta\u003c/strong\u003e, \u003cstrong\u003e3ua\u003c/strong\u003e) to be obtained with good enantioselectivities (70\u0026ndash;88% ee), albeit in modest yields (45\u0026thinsp;\u0026minus;\u0026thinsp;75%).\u003c/p\u003e\n\u003cp\u003eNext, the \u003cem\u003eN\u003c/em\u003e-aryl substitution of the sulfenamides was examined. Both electron-donating (\u003cstrong\u003e1v\u003c/strong\u003e) and electron-withdrawing aryls (\u003cstrong\u003e1w\u003c/strong\u003e, \u003cstrong\u003e1x, 1y\u003c/strong\u003e) gave the desired products (\u003cstrong\u003e3va\u003c/strong\u003e-\u003cstrong\u003eya\u003c/strong\u003e) with 60\u0026ndash;84% yields and 83\u0026ndash;94% enantioselectivity. Importantly, a set of functional groups, including aldehyde (\u003cstrong\u003e1z\u003c/strong\u003e), ketone (\u003cstrong\u003e1aa\u003c/strong\u003e), ester (\u003cstrong\u003e1y\u003c/strong\u003e), and even the polymerizable vinyl group (\u003cstrong\u003e1ab\u003c/strong\u003e), were well tolerated in the protocol to deliver the corresponding chiral diaryl sulfilimines (\u003cstrong\u003e3ya\u003c/strong\u003e-\u003cstrong\u003eaba\u003c/strong\u003e) in good yields (77\u0026thinsp;\u0026minus;\u0026thinsp;89%) with good to excellent enantiocontrol (74\u0026thinsp;\u0026minus;\u0026thinsp;93% ee). These results highlight the advantages of this protocol as the aldehyde and terminal alkene are not tolerated in the previously reported route, oxidative imination of sulfides, due to the competing oxidation. Sterically hindered \u003cem\u003eN\u003c/em\u003e-(2-Br-phenyl) sulfenamide (\u003cstrong\u003e1ac\u003c/strong\u003e) reacted with \u003cstrong\u003e2a\u003c/strong\u003e under the optimal conditions to afford \u003cstrong\u003e3aca\u003c/strong\u003e in 74% with 84% ee. \u003cem\u003emeta\u003c/em\u003e-Substituted \u003cem\u003eN\u003c/em\u003e-aryl sulfenamides, including 3-methoxy (\u003cstrong\u003e1ad\u003c/strong\u003e), 3-iodo (\u003cstrong\u003e1ae\u003c/strong\u003e), and 3-acetamido (\u003cstrong\u003e1af\u003c/strong\u003e), were competent coupling partners to deliver sulfilimines \u003cstrong\u003e3ada\u003c/strong\u003e-\u003cstrong\u003efa\u003c/strong\u003e in 71\u0026thinsp;\u0026minus;\u0026thinsp;81% yields with 74\u0026thinsp;\u0026minus;\u0026thinsp;91% ee. Heteroaromatic sulfenamides, such as pyridines \u003cstrong\u003e1ag\u003c/strong\u003e, \u003cstrong\u003e1ah\u003c/strong\u003e and pyrimidine \u003cstrong\u003e1ai\u003c/strong\u003e, also proved to be potent coupling partners to furnish chiral \u003cem\u003eN\u003c/em\u003e-heterocyclic diaryl sulfilimines \u003cstrong\u003e3aga\u003c/strong\u003e-\u003cstrong\u003eia\u003c/strong\u003e in satisfactory yields with good stereocontrol.\u003c/p\u003e\n\u003cp\u003eThe use of alternate arylboronic acids was next interrogated. The 2-naphthalene (\u003cstrong\u003e2b\u003c/strong\u003e) variant again proved effective at this position. Electron-donating substrates including 4-OBn (\u003cstrong\u003e2c\u003c/strong\u003e), 4-\u003csup\u003e\u003cem\u003en\u003c/em\u003e\u003c/sup\u003ebutyl (\u003cstrong\u003e2d\u003c/strong\u003e), 4-TMS (\u003cstrong\u003e2e\u003c/strong\u003e), 4-PhO (\u003cstrong\u003e2f\u003c/strong\u003e), and 4-Ph (\u003cstrong\u003e2g\u003c/strong\u003e) and electron-neutral substrates 4-MeS (\u003cstrong\u003e2h\u003c/strong\u003e) and 4-H (\u003cstrong\u003e2i\u003c/strong\u003e) furnished the products \u003cstrong\u003e3ab\u003c/strong\u003e-\u003cstrong\u003ei\u003c/strong\u003e in moderate to good yields while sustaining good stereoselectivities. In particular, \u003cstrong\u003e3ah\u003c/strong\u003e is synthetically intractable via the classic imination of sulfides, since it contains two functionalities with different oxidation states of sulfur. Importantly, labile trimethylsilyl (\u003cstrong\u003e2e\u003c/strong\u003e) or vinyl (\u003cstrong\u003e1j\u003c/strong\u003e) groups were also amendable to the chemistry, providing a means for later modification via other orthogonal processes. Moreover, \u003cem\u003emeta\u003c/em\u003e-substituted arylboronic acids (\u003cstrong\u003e2k\u003c/strong\u003e-\u003cstrong\u003em\u003c/strong\u003e) were effective. Finally, the heterocyclic benzofuranyl boronic acid (\u003cstrong\u003e2n\u003c/strong\u003e) generated \u003cstrong\u003e3an\u003c/strong\u003e with good selectivity (87% ee).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSynthetic Utility.\u003c/strong\u003e A major source of nitrogen-based chiral ligands is inexpensive and abundant natural \u003cem\u003eL\u003c/em\u003e-amino acids, which, in turn, limits the availability of the enantiomeric congeners. In this instance, the opposite enantiomeric ligand of \u003cstrong\u003eL10\u003c/strong\u003e is derived from an expensive \u003cem\u003eD\u003c/em\u003e-amino acid. Thus, generation of both of enantiomeric products from the same, less expensive chiral ligand would be a distinct advantage. Simply exchanging the aryl groups of the sulfenamide and arylboronic acid substrates enabled such an outcome. Thus, synthesis of both enantiomers of sulfilimine \u003cstrong\u003e3dl\u003c/strong\u003e was achieved by using \u003cstrong\u003e1d\u003c/strong\u003e with \u003cstrong\u003e2l\u003c/strong\u003e vs \u003cstrong\u003e1o\u003c/strong\u003e with \u003cstrong\u003e2o\u003c/strong\u003e under the identical catalytic conditions (Scheme \u003cspan class=\"InternalRef\"\u003e2a\u003c/span\u003e). In addition, the chiral S(IV)-based sulfilimines obtained by our enantioselective Chan-Lam \u003cem\u003eS\u003c/em\u003e-alkylation could serve as versatile intermediates to access to chiral S(VI)-based sulfoximines. Exposure of sulfilimine \u003cstrong\u003e3va\u003c/strong\u003e to NaClO leads to the formation of sulfoximine \u003cstrong\u003e4a\u003c/strong\u003e with no detectable erosion of enantiomeric excess at the sulfur stereocenter\u003csup\u003e32\u003c/sup\u003e (Scheme \u003cspan class=\"InternalRef\"\u003e2b\u003c/span\u003e). Next, we showed the synthetic utility of this method due to the emerging role of sulfilimines in medicinal chemistry. Inspired by the elaboration of pan-CDK inhibitor Bay1000394 from Bayer by switching the sulfonamide to a sulfoximine as the pharmocophore\u003csup\u003e33\u003c/sup\u003e, two sulfilimine analogues of patented bioactive molecules were generated using our enantioselective Chan-Lam coupling as the key step (Scheme \u003cspan class=\"InternalRef\"\u003e2c\u003c/span\u003e). Sulfilimine \u003cstrong\u003e9\u003c/strong\u003e, an analog of an agonist (\u003cstrong\u003e9\u0026rsquo;\u003c/strong\u003e) of AMP-activated protein kinase (AMPK) in the treatment of degenerative neurological diseases\u003csup\u003e34\u003c/sup\u003e, could be synthesized in three steps with 60% overall yield and 80% ee. Compound \u003cstrong\u003e14\u003c/strong\u003e, an analog of the sulfoxide-based histone-lysine \u003cem\u003eN\u003c/em\u003e-methyltransferase EZH2 Inhibitor (\u003cstrong\u003e14\u0026rsquo;\u003c/strong\u003e)\u003csup\u003e35\u003c/sup\u003e, was concisely assembled in four steps with a 28% yield and 86% ee. Remarkably, compound \u003cstrong\u003e12\u003c/strong\u003e bearing a labile activated ester group reacted efficiently with \u003cstrong\u003e2a\u003c/strong\u003e to deliver the corresponding chiral sulfilimine in good stereoselectivity, underlining the broad functional group compatibility. Overall, the method described herein offers a versatile platform to afford a range of derivatives in a step-economic manner.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMechanistic Studies.\u003c/strong\u003e To understand the factors controlling chemo- and enantioselectivity, the mechanism was probed using density functional theory (DFT) [UM06/6-311\u0026thinsp;+\u0026thinsp;+\u0026thinsp;G(d,p)-SDD(Cu)-CPCM(DME)//UB3LYP-D3/6-31G(d)-SDD(Cu)\u003csup\u003e36\u0026ndash;44\u003c/sup\u003e, see Supporting Information for full computational details]. Initially, Cu\u003csup\u003eII\u003c/sup\u003e complex \u003cstrong\u003e1\u0026rsquo;\u003c/strong\u003e forms the pre-reacting complex \u003cstrong\u003e1\u003c/strong\u003e with the incoming aryl boronic acid (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea, downhill in energy by 2.0 kcal/mol). This complex then undergoes transmetalation (via [\u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e], 3.9 kcal/mol) to form intermediate \u003cstrong\u003e2\u003c/strong\u003e (\u0026minus;25.1 kcal/mol) following dissociation of boric acid. Next, sulfenamide coordinates to \u003cstrong\u003e2\u003c/strong\u003e to form \u003cstrong\u003e2a\u0026rsquo;\u003c/strong\u003e (\u0026minus;20.6 kcal/mol).\u003c/p\u003e\n\u003cp\u003eIntermediate \u003cstrong\u003e2a\u0026rsquo;\u003c/strong\u003e can undergo kinetically controlled \u003cem\u003eS\u003c/em\u003e-arylation (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb, blue pathway) or the higher energy \u003cem\u003eN\u003c/em\u003e-arylation (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb, red pathway). For the \u003cem\u003eS\u003c/em\u003e-arylation, Cu\u003csup\u003eII\u003c/sup\u003e intermediate \u003cstrong\u003e2a\u0026rsquo;\u003c/strong\u003e first undergoes disproportionation with Cu\u003csup\u003eII\u003c/sup\u003e intermediate \u003cstrong\u003e1\u0026rsquo;\u003c/strong\u003e to form Cu\u003csup\u003eIII\u003c/sup\u003e complex \u003cstrong\u003e2\u0026rsquo;\u003c/strong\u003e (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb, blue, \u0026minus;22.4 kcal/mol) and LCu\u003csup\u003eI\u003c/sup\u003e hydroxide. Thiophene carboxylate dissociates from the inner coordination sphere of the Cu\u003csup\u003eIII\u003c/sup\u003e complex to form the square pyramidal Cu\u003csup\u003eIII\u003c/sup\u003e cationic complex \u003cstrong\u003e2c\u0026rsquo;\u003c/strong\u003e. Cystallographic evidence of various square pyramidal cationic Cu\u003csup\u003eIII\u003c/sup\u003e species supports the formation of such an intermediate\u003csup\u003e45\u003c/sup\u003e. Furthermore, the imidazole ring of \u003cstrong\u003eL2\u003c/strong\u003e, a strong sigma donor, is trans to sulfur, (see Figure S1). Next, sulfur-arylation occurs via [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e] (overall energetic span\u003csup\u003e46\u003c/sup\u003e of 8.0 kcal/mol from intermediate \u003cstrong\u003e2a\u0026rsquo;\u003c/strong\u003e) to give protonated \u003cem\u003eS\u003c/em\u003e-arylation product \u003cstrong\u003e3\u0026rsquo;-S\u003c/strong\u003e. Finally, deprotonation of the nitrogen atom gives the final product \u003cstrong\u003e3-S\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eTo understand the chemoselectivity observed in this transformation, we also computed the formation of the \u003cem\u003eN\u003c/em\u003e-aryl product (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb, red). From intermediate \u003cstrong\u003e2a\u0026rsquo;\u003c/strong\u003e, deprotonation must occur prior to \u003cem\u003eN\u003c/em\u003e-arylation in order for the nitrogen atom to react (for a comparison of energetic spans of \u003cem\u003eN\u003c/em\u003e-arylation before and after deprotonation, see Figure S2). The nitrogen atom of the sulfenamide undergoes deprotonation with NMe\u003csub\u003e3\u003c/sub\u003e as the base (as a simplified model for \u003csup\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sup\u003ePr\u003csub\u003e2\u003c/sub\u003eNEt) via \u003cstrong\u003e2\u0026rsquo;-TS\u003c/strong\u003e (overall energetic span of 14.0 kcal/mol) to form intermediate \u003cstrong\u003e2d\u0026rsquo;\u003c/strong\u003e. Disproportionation of Cu\u003csup\u003eII\u003c/sup\u003e species \u003cstrong\u003e2d\u0026rsquo;\u003c/strong\u003e with Cu\u003csup\u003eII\u003c/sup\u003e intermediate \u003cstrong\u003e1\u0026rsquo;\u003c/strong\u003e yields Cu\u003csup\u003eIII\u003c/sup\u003e intermediate \u003cstrong\u003e2b\u0026rsquo;\u003c/strong\u003e and LCu\u003csup\u003eI\u003c/sup\u003e hydroxide. From intermediate \u003cstrong\u003e2b\u0026rsquo;\u003c/strong\u003e, \u003cem\u003eN\u003c/em\u003e-arylation occurs via \u003cstrong\u003e[2\u0026rsquo;-4]\u003c/strong\u003e, giving the thermodynamically favored product \u003cstrong\u003e4\u003c/strong\u003e. Notably, \u003cem\u003eS\u003c/em\u003e-arylation is under kinetic control as the energetic span to form the product \u003cstrong\u003e3\u0026rsquo;-S\u003c/strong\u003e is lower by 6.0 kcal/mol, explaining the observed experimental chemoselectivity in this transformation. This kinetic control overcomes the far greater stability of the \u003cem\u003eN\u003c/em\u003e-aryl product relative to the \u003cem\u003eS\u003c/em\u003e-aryl product\u003csup\u003e30\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eNext, we delved further into the chemoselectivity by comparing the experimental results with different ligands to our computational results (see Figures S3-4 in the Supporting Information). Notably, ligand \u003cstrong\u003eL47\u003c/strong\u003e, which gives a greater amount of \u003cem\u003eN\u003c/em\u003e-arylation product, has a smaller difference between energy spans for \u003cem\u003eS\u003c/em\u003e-arylation and \u003cem\u003eN\u003c/em\u003e-arylation (see Table S17). This agreement of the experimental results with our computational findings provides additional support for the proposed mechanism.\u003c/p\u003e\n\u003cp\u003eFinally, the origin of enantioselectivity in this transformation was investigated. The lowest energy conformations of the \u003cem\u003eS\u003c/em\u003e-arylation transition state leading to (\u003cem\u003eS\u003c/em\u003e)-enantiomer and (\u003cem\u003eR\u003c/em\u003e)-enantiomer are shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ec (for comparison of energetics with different methods, see Tables S18-20). Upon initial inspection of the transition state geometries, it is unclear what factors control the excellent enantioselectivity observed in this transformation (see Figure S5). As a result, interaction/distortion analysis was performed as described by Houk and Bickelhaupt\u003csup\u003e47\u003c/sup\u003e (see Figure S6) in which the favorable interaction energy between the copper-ligand (CuL) and aryl substrate is compared with the energy required to distort the intermediates into the transition state geometries. The distortion in the LCu component of [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eR\u003c/strong\u003e\u003c/sub\u003e is 27.2 kcal/mol, which is much greater than the analogous distortion in the [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eS\u003c/strong\u003e\u003c/sub\u003e (12.0 kcal/mol). This distortion in the LCu component can be observed in the overlaid transition state and intermediate geometries given in Figure S7. However, the interaction energy between the two LCu and aryl substrate components is greater in [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eR\u003c/strong\u003e\u003c/sub\u003e, giving an overall energy of \u0026minus;34.4 kcal/mol compared to \u0026minus;34.1 kcal/mol in [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eS\u003c/strong\u003e\u003c/sub\u003e. Based on this analysis, the observed enantioselectivity does not arise predominantly from a difference in interaction energy. Rather, the difference in distortion need to accommodate the two transition states drives the enantioselectivity.\u003c/p\u003e\n\u003cp\u003eThus, the difference in free energy between [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eR\u003c/strong\u003e\u003c/sub\u003e and [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eS\u003c/strong\u003e\u003c/sub\u003e was further explored. Since [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eS\u003c/strong\u003e\u003c/sub\u003e is favored by 2.9 kcal/mol in free energy, but only by 0.3 kcal/mol in enthalpy, we attributed the enantioselectivity to this free energy difference. On further examination of the transition state geometries (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ec), the \u003cem\u003eS\u003c/em\u003e-arylation leading to the (\u003cem\u003eS\u003c/em\u003e)-enantiomer has an 8-membered ring involved in the bond formation whereas [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eR\u003c/strong\u003e\u003c/sub\u003e has a 6-membered ring. Since the 8-membered ring is more flexible, it is more entropically favored, which results in a favorable free energy for [\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003csub\u003e\u003cstrong\u003eS.\u003c/strong\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003eFinally, the decrease in the observed experimental enantioselectivity when the substrate is changed from the unsubstituted phenyl substrate (left, Figure S7) to the \u003cem\u003ep\u003c/em\u003e-NO\u003csub\u003e2\u003c/sub\u003e substituted substrate (right, Figure S7) was computed with \u003cstrong\u003eL10\u003c/strong\u003e ligand. In agreement with the observed experimental decrease in enantioselectivity (from 92% ee to 56% ee), the free energy difference also decreases (from 2.9 kcal/mol to 0.7 kcal/mol).\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, we have introduced a highly chemoselective and enantioselective Chan-Lam coupling of sulfenamides with arylboronic acids to synthesize a diverse range of diaryl sulfilimines containing a stereogenic sulfur center. A copper catalyst generated from the newly developed 2-pyridyl \u003cem\u003eN\u003c/em\u003e-phenyl imidazole ligand enables effective enantiocontrol by means of a well-defined chiral environment and high reactivity that outcompetes the background racemic transformation. With this strategy, a single chiral ligand can deliver either enantiomeric product by exchanging the aryl groups of the sulfenamide and arylboronic acid substrates, thereby circumventing the need to prepare the enantiomeric ligands from the unnatural \u003cem\u003eD\u003c/em\u003e-amino acids. In addition, the synthetic utility of this unprecedented asymmetric coupling was underscored by synthesis of two sulfilimine-analogs of patented bioactive molecules. In concert with experimental data, computational studies reveal the unconventional chemoselectivity favoring C-S bond over C-N bond was enabled by disproportionation of Cu(II) complexes prior to deprotonation of sulfenamides. Furthermore, the excellent enantioselectivity arises from the difference of entropy between the transition states. The protocol described herein represents the first enantioselective Chan-Lam coupling, which is anticipated to serve as a powerful tool to prepare chiral scaffolds in medicinal chemistry and organic synthesis.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eGeneral Procedure for Catalysis.\u003c/strong\u003e To an oven-dried microwave vial equipped with a stir bar was added sulfenamide \u003cstrong\u003e1\u003c/strong\u003e (0.10 mmol), arylboronic acid \u003cstrong\u003e2\u003c/strong\u003e (0.2 mmol, 2.0 equiv), CuTc (1.9 mg, 0.01 mmol), \u003cstrong\u003eL10\u003c/strong\u003e (5.5 mg, 0.015 mmol), CsF (7.6 mg, 0.05 mmol), and Na\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e (21.2 mg, 0.2 mmol). Then, the microwave vial was sealed with a cap. Oxygen was purged/vacuumed three times through a three-way valve, and the microwave tube turned to an oxygen atmosphere. DME (1.0 mL) was added into the reaction vial via syringe, and the reaction solution was stirred at room temperature under the oxygen atmosphere for 12 h. Upon completion of the reaction, the vial was opened to air, and the solution was concentrated under reduced pressure. The crude product was purified by flash chromatography, as outlined below, to afford the pure product.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDetailed experimental procedures, characterization data, NMR spectra of new compounds, detailed computational study, and calculated structures are available within Supplementary Information. Any further relevant data are available from the authors upon reasonable request.\u003c/p\u003e\n\u003cp\u003eCCDC 2215359 (3ba) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystal-lographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eACKNOWLEDGMENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eT.J. thanks Guangdong-Joint Foundation of Shenzhen (2021B1515120046, 2022B1515120075), Natural Science Foundation of Guangdong Province (2022A1515011770), and the Science and Technology Innovation Commission of Shenzhen Municipality (JCYJ20220818101404010, 20220815113214003) for financial support. M.C.K. thanks the NIH (R35 GM131902) for financial support and XSEDE (TG-CHE120052) for computational support. We are very grateful to Dr. Yang Yu and Dr. Xiaoyong Chang (both at SUSTech) for HRMS and X-ray crystallography respectively. We acknowledge the assistance of SUSTech Core Research Facilities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eT.J. conceived and supervised the project. Q.L., X.Z. and Z.X. performed the experiments. M.C.K. directed the part of computational study. M.E.R. carried out computational study. T.J., Q.L. and X.Z. analyzed the data. All authors participated in writing the manuscript. Q.L., X.Z. and M.E.R. contributed equally.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupplementary information is available for this paper.\u003c/p\u003e\n\u003cp\u003eCorrespondence and requests for materials should be addressed to T.J.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGilchrist, T.L. \u0026amp; Moody, C.J. The Chemistry of Sulfilimines. \u003cem\u003eChem. Rev.\u003c/em\u003e \u003cstrong\u003e77\u003c/strong\u003e, 409-435 (1977).\u003c/li\u003e\n\u003cli\u003eFurukawa, N. \u0026amp; Oae, S. Sulfilimines. Synthetic Applications and Potential Utilizations. \u003cem\u003eInd. Eng. Chem. Prod. Res. 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How to Conceptualize Catalytic Cycles? The Energetic Span Model. \u003cem\u003eAcc. Chem. Res.\u003c/em\u003e \u003cstrong\u003e44\u003c/strong\u003e, 101-110 (2011).\u003c/li\u003e\n\u003cli\u003eBickelhaupt, F.M. \u0026amp; Houk, K.N. Analyzing Reaction Rates with the Distortion/Interaction-Activation Strain Model. \u003cem\u003eAngew. Chem., Int. Ed.\u003c/em\u003e \u003cstrong\u003e56\u003c/strong\u003e, 10070-10086 (2017).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 and 2 are available in the Supplementary Files section.\u003c/p\u003e "},{"header":"Schemes","content":"\u003cp\u003eSchemes 1 and 2 are available in the Supplemental Files section.\u003c/p\u003e"},{"header":"Supplementary Information","content":"\u003cp\u003eThe Supplementary Information files are not available with this version.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Southern University of Science and Technology","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-2779487/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2779487/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eChan-Lam coupling constructs C-N, C-O and C-S bonds by coupling nucleophiles with boronic acids using copper complexes. 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