X=Y–ZH Systems as potential 1,3-dipoles. Part 52: Fused-ring forming electrophile induced oxime→nitrone→cycloaddition cascades

Abstract

Electrophile induced cyclisation of oximes onto endocyclic alkenes and exo-methylene cycloalkanes occurs stereo- and regio-specifically generating cis-fused bicyclic nitrones in good yield. Subsequent facially selective cycloaddition with N-methylmaleimide occurs in good yield. The sequence may be carried out as a one-pot procedure and results in the formation of 4 bonds, 2 rings and 6 stereocentres.