Ni-Catalyzed [8+3] cycloaddition of tropones with 1,1-cyclopropanediesters

Abstract

A variety of cycloheptapyrane derivatives were prepared via Ni-catalyzed formal [8+3] cycloaddition of tropones with 1,1-cyclopropanediesters. The asymmetric version of the process can be achieved using either an enantiomerically enriched cyclopropane as the starting material or a racemic cyclopropane and a chiral Lewis acid.