Asymmetric Michael addition of α-hydroxyketones to nitroolefins catalyzed by chiral diamine

[GRAPHIC] The regio-, stereo-, and enantioselective direct Michael addition of alpha-hydroxyketones to beta-aryinitroolef ins catalyzed by N-/Pr-2,2'-bipyrrolidine is described. The formation of an internal hydrogen bond between the OH group of alpha-hydoxyacetone and the tertiary nitrogen of the catalyst leads to the formation of a rigid cis enamine intermediate that explains the inversion of the expected diastereoselectivity and the very high ee's.