A Divergent Synthesis of Essentially Enantiopure syn- and anti-Propionate Aldol Adducts Based on the Chiral 1,3,2-Oxazaborolidin-5-one-Promoted Asymmetric Aldol Reaction Followed by Diastereoselective Radical Reduction

摘要

Essentially, enantiopure syn- and anti-propionate aldol adducts were divergently synthesized using a novel strategy which utilizes both the highly enantioselective 1,3,2-oxazaborolidin-5-one-promoted aldol reaction with a ketene silyl acetal derived from ethyl 2-bromo propionate and a highly diastereoselective radical debromination reaction. These pro-cedures provide yields that increase to a level available for practical synthesis.