Expounding the Mechanism and Regioselectvity of [3+2] Cycloloaddition between N-phenylmethanimine oxide Nitrone and 2-methylene-1,3-dithiolane 1,3-dioxide

Abstract The molecular electron density theory (MEDT) framework has been used to analyze the [3 + 2] cycloaddition reaction (32CA) between 2-methylene-1,3-dithiolane 1,3-dioxide MDD-2 and N-phenylmethanimine oxide nitrone NIT-1 at the B3LYP/6-311 + + G(d,p) level of theory. The Parr functions and the energy studies clearly reveal that this reaction is extremely regioselective, which is in perfect agreement with the experimental results. This 32CA zwitter-ionic type reaction exhibits high free energies of activation between 21.23 and 23.03 kcal mol-1. By analyzing the chemical mechanism in terms of bond evolution theory (BET), which discloses a variety of fluctuations in the electron density along the reaction route, a one-step mechanism with extremely asynchronous transition states is revealed.