Racemic and asymmetric cobalt-catalysed reductive aldol couplings of α,β-unsaturated amides with ketones

In the presence of diethylzinc as a stoichiometric reductant, substoichiometric quantities of an appropriate cobalt source catalyse diastereoselective reductive aldol coupling reactions of alpha,beta-unsaturated amides with ketones. The use of a readily available oxazolidine as a chiral auxiliary imparts high levels of asymmetric induction in these reactions. (C) 2008 Elsevier Ltd. All rights reserved.