Efficient enantio- and diastereoselective synthesis of enantiopure syn-alpha-bromo-beta-hydroxy-alpha-methylpropionate esters and their-cis-alpha,beta-epoxy derivatives based on a chiral oxazaborolidinone-promoted asymmetric aldol reaction

摘要

syn-alpha-Bromo-beta-hydroxy-alpha-methylpropionate esters were prepared in high diastereoselectivity with essentially enantiopure state by employing the chiral oxazaborolidinone-promoted asymmetric aldol reaction with beta-bromo-beta-methylketene silyl acetal. The subsequent subjection of the alpha-bromo-beta-hydroxy esters to basic conditions led to the quantitative transformation to the corresponding enantiopure cis-alpha,beta-epoxy derivatives, (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 11]