Catalytic direct asymmetric Michael reactions: taming naked aldehyde donors.

ABSTRACT

[reaction--see text] Direct catalytic enantio- and diastereoselective Michael addition reactions of unmodified aldehydes to nitro olefins using (S)-2-(morpholinomethyl)pyrrolidine as a catalyst are described. The reactions proceed in good yield (up to 96%) in a highly syn-selective manner (up to 982) with enantioselectivities approaching 80%. The resulting gamma-formyl nitro compounds are readily converted to chiral, nonracemic 3,4-disubstituted pyrrolidines.