Enantioselective Organocatalytic Michael−Wittig−Michael−Michael Reaction: Dichotomous Construction of Pentasubstituted Cyclopentanecarbaldehydes and Pentasubstituted Cyclohexanecarbaldehydes

Abstract

Michael addition of carbethoxymethylenetriphenylphosphorane (a Wittig reagent) to nitroalkenes, followed by a reaction with ethyl formylformate and cinnamaldehydes, or formaldehyde and cinnamaldehydes, provided the respective pentasubstituted cyclopentanecarbaldehydes bearing a quaternary carbon center and pentasubstituted cyclohexanecarbaldehydes having five contiguous stereocenters with excellent enantioselectivities (up to >99% ee).