Asymmetric α-Hydroxylation of Tetralone-Derived β-Ketoesters by Using a Guanidine-Urea Bifunctional Organocatalyst in the Presence of Cumene Hydroperoxide.

Highly enantioselective catalytic oxidation of 1-tetralone-derived β-keto esters was achieved by using a guanidine-urea bifunctional organocatalyst in the presence of cumene hydroperoxide (CHP), a safe, commercially available oxidant. The α-hydroxylation products were obtained in 99 % yield with up to 95 % enantiomeric excess ( ee). The present oxidation was successfully applied to synthesize a key intermediate of the anti-cancer agent daunorubicin ( 2). [ABSTRACT FROM AUTHOR]