Invertible enantioselectivity in 6'-deoxy-6'-acylamino-beta-isocupreidine-catalyzed asymmetric aza-Morita-Baylis-Hillman reaction: key role of achiral additive.
Résumé
The beta-ICD (1a) or beta-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 beta-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.