Rhodium(II)/Chiral Phosphoric Acid-Cocatalyzed Enantioselective O-H Bond Insertion of α-Diazo Esters.

A rhodium(II)/chiral phosphoric acid system has been developed for the asymmetric catalytic insertion of α-diazo esters into the O-H bond of carboxylic acids to generate an array of synthetically useful α-hydroxy ester derivatives in good ee (up to 95% ee). Furthermore, the substrate scope could be successfully extended to a range of phenols and alcohols with high yield (up to 92%) and excellent enantioselectivity (up to 97%) under mild reaction conditions. Additionally, a density functional theory (DFT) study was performed to elucidate the reaction mechanism. [ABSTRACT FROM AUTHOR]