화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.133, No.40, 15882-15885, 2011
An Enantioselective, Intermolecular alpha-Arylation of Ester Enolates To Form Tertiary Stereocenters
In transition-metal catalyzed, asymmetric alpha-arylation of carbonyl compounds, formation of tertiary centers with high enantioselectivity is a longstanding problem, due to easy enolization of the monoarylation products. Herein, we report such examples using a palladium catalyst supported by a new, (R)-H(8)-BINOL-derived monophosphine. Silyl ketene acetals, together with a weakly basic activator, were used as equivalents of ester anions, and they reacted smoothly with aryl triflates in excellent enantiomeric excess (ee). The usefulness of the reaction was demonstrated in a gram-scale synthesis of (S)-Naproxen in 92% ee.