Selective α-reduction of α,β-epoxycarbonyls with silyllithium reagents

CHED 315

Samantha C. Reynolds, reynoldss2@winthrop.edu and Aaron M. Hartel, hartela@winthrop.edu. Department of Chemistry, Winthrop University, Rock Hill, SC 29733

The selective α-reduction of α-epoxycarbonyls to the corresponding β-hydroxycarbonyls was explored using silyllithium reagents.  The proposed mechanism for the reaction involves a nucleophilic attack by the silicon atom on the carbonyl of the substrate, followed by a Brook rearrangement and concomitant epoxide ring opening.  The resulting silicon-oxygen bond is then cleaved by a second equivalent of the silyllithium reagent to afford the β-hydroxycarbonyl product.  A variety of differentially substituted α-epoxycarbonyls were synthesized and treated with excess silyllithium reagent in order to determine the synthetic utility of the reaction.