Invertible Enantioselectivity in 6′-Deoxy-6′-acylamino-β-isocupreidine-Catalyzed Asymmetric Aza-Morita−Baylis−Hillman Reaction: Key Role of Achiral Additive

The β-ICD (1a) or β-ICD-amide (1e)-catalyzed aza-Morita−Baylis−Hillman reaction between N-sulfonylimines 3 and alkyl vinyl ketones 4 produced the (R)-enriched adducts 5. By adding a catalytic amount of β-naphthol (2a), the enantioselectivity of the same reaction was inversed leading to (S)-5 in excellent yields and enantioselectivities. Both aromatic and aliphatic imines are accepted as substrates for this reaction.