Alpha,alpha-disubstituted boron enolates in the asymmetric synthesis of quaternary carbon centers.
[reaction: see text] Reduction of alpha,alpha-disubstituted thioglycolate amides with lithium di-tert-butylbiphenylide affords alpha,alpha-disubstituted enolates with high Z/E selectivity. Transmetalation of the enolates with dicyclohexylboron bromide facilitates highly diastereoselective aldol reaction with aromatic and alpha,beta-unsaturated aldehydes.
Burke
E Diane
ED
Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec, Canada, H3A 2K6.
Gleason
James L
JL