Nucleophilic carbene-catalyzed redox-esterification reaction of α-halo-α,β-unsaturated aldehyde

A nucleophilic carbene catalyzed redox esterification between alpha-halo-alpha,beta-unsaturated aldehydes and various alcohols has been developed. Interestingly, the reaction provided alpha,beta-unsaturated esters instead of the saturated alpha-halo substituted esters as the only product in good to high yield with excellent transselectivity, presumably via the umpolung-halo-elimination pathway. (C) 2012 Elsevier Ltd. All rights reserved.