title: High stereocontrol in aldol reaction with ketones: enantioselective synthesis of beta-hydroxy gamma-ketoesters by ester enolate aldol reactions with 2-acyl-2-alkyl-1,3-dithiane 1-oxides
abstract: The asymmetric aldol reaction of 1,2-diketones, masked as nonracemic 2-acyl dithiane oxides, with lithium enolates derived from several esters and lactones, proceeds with a high degree of stereocontrol at both carbonyl and enolate prochiral centers, the stereocontrol mainly determined by the configuration of the sulfoxide sulfur atom. The sense of induced stereochemistry observed for ester enolates is different from that seen for lactone enolates. Hydrolysis of the dithiane oxide units of the major diastereoisomerically pure aldol products affords enantiomerically pure tertiary alpha-substituted beta-hydroxy-gamma-ketoesters.
authors.affiliation: Departamento de Quimica Organica, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid, Spain, and Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, England.
authors.lastname: Garcia Ruano JL
authors.initials: D
authors.lastname: Barros
authors.initials: MC
authors.lastname: Maestro
authors.initials: AM
authors.lastname: Slawin
authors.initials: PC
authors.lastname: Page