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 I (R = Ph, i-Pr, n-Pr, etc.) 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 Et 2-bromo propionate and a highly diastereoselective radical debromination reaction. These procedures provide yields that increase to a level available for practical synthesis. [on SciFinder(R)]