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

Essentially, enantiopure syn- and anti-propionate aldol adducts were diverg ently synthesized using a novel strategy which utilizes both the highly ena ntioselective 1,3,2-oxazaborolidin-5-one-promoted aldol reaction with a ket ene silyl acetal derived from ethyl 2-bromo propionate and a highly diaster eoselective radical debromination reaction. These procedures provide yields that increase to a level available for practical synthesis.