Cobalt-Catalyzed Diastereoselective Reductive Mannich Reaction of Amides

Significance

Earlier, the authors have reported the aldol reactions of zinc enolate generated via conjuate reduction by treatment of α,β-unsaturated amides with diethylzinc and a substoichiometric quantity of a cobalt salt (Org. Lett. 2006, 8, 3729). This present study reports Mannich reactions between aldimines and zinc enolates generated by conjugate reduction. Although yields and diastereoselectivities were moderate, it is noted that anti products were obtained as the major isomers.