Strong Bases and Weak Anions in Catalytic C–H Insertion Reactions of Vinyl Carbocations

Here we report the surprising discovery that high-energy vinyl carbocations can be generated under strongly basic conditions, and that they engage in intramolecular sp3 C–H insertion reactions through the catalysis of commercially available weakly coordinating anion salts. This approach relies on the unconventional combination of lithium hexamethyldisilazide base and the commercially available catalyst, triphenylmethylium tetrakis(pentafluorophenyl)borate. These reagents form a catalytically active lithium species that enables the application of vinyl cation C–H insertion reactions to heteroatomcontaining substrates.