Michael Addition Catalyzed by a Chiral Bimorpholine

Significance

A new class of catalysts has been added to the ever increasing list of organocatalysts for the asymmetric Michael addition. The authors report the 3,3′-bimorpholine aminocatalyst 1 for the reaction of nitroolefins 2 and aldehydes 3 to give the corresponding 1,4-adducts 4. Even an aliphatic nitroolefin could be converted with high enantioselectivity (85%), although the reaction time had to be drastically elongated in this case to give reasonable yield. Also, first results using vinyl sulfone 6 and iso-valeraldehyde (5) to produce Michael product 7 are described, but only low enantioselectivity (55%) was achieved.