Catalytic Asymmetric Direct Vinylogous Michael Addition of γ-Aryl-Substituted Deconjugated Butenolides to Nitroolefins and N-Phenylmaleimide

Abstract

Direct asymmetric vinylogous Michael reactions of gamma-aryl-substituted deconjugated butenolides with nitroolefins and N-phenylmaleimide are described using bifunctional thiourea derivatives as the catalyst. The resulting butenolide derivatives containing adjacent quaternary and tertiary stereocenters are obtained in good yields (54-90%) and with excellent enantioselectivities (er up to 99:1) and high diastereoselectivities (dr up to > 20:1).