HFIP-promoted synthesis of bicyclo[2.1.1]-hexanes through formal [2π+2σ] cycloaddition of bicyclo[1.1.0]butanes with α-cyano chalcones

Abstract

A HFIP-promoted formal [2π+2σ] cycloaddition of bicyclo[1.1.0]butanes with α-cyano chalcones has been reported, in which HFIP acts as the hydrogen-bond activator of both substrates, the stabilizer of carbocations and a co-solvent. This approach demonstrates good functional group tolerance and high diastereoselectivity, providing a facile methodology for synthesis of bicyclo[2.1.1]hexanes under mild conditions.