Enantioselective Epoxypyrrolidines via a Tandem Cycloaddition/Autoxidation in Air and Mechanistic Studies

A tandem cycloaddition/autoxidation reaction between heterocyclic ketene aminals and diazoester in air is described for the enantioselective preparation of epoxypyrrolidines. Notably, the results of mechanistic studies suggest that epoxide was oxidized from an sp3 C–C single bond, which is of mechanistic and practical interest as this protocol may be suitable for constructing other bioactive heterocyclic epoxides.