An efficient asymmetric hydroesterfication of diarylmethyl carbinols is developed for the first time with a Pd‐WingPhos catalyst, resulting in a series of chiral 4‐aryl‐3,4‐dihydrocoumarins in excellent enantioselectivities and good yields. The method features mild reaction conditions, a broad substrate scope, use of easily accessible starting materials, and low palladium loadings. A plausible stereochemical
Palladium(II)-Catalyzed Direct Carboxylation of Alkenyl C–H Bonds with CO<sub>2</sub>
作者:Kota Sasano、Jun Takaya、Nobuharu Iwasawa
DOI:10.1021/ja405503y
日期:2013.7.31
Pd-catalyzed direct carboxylation of alkenyl C-H bonds with carbon dioxide was realized for the first time. Treatment of 2-hydroxystyrenes and a catalytic amount of Pd(OAc)2 with Cs2CO3 under atmospheric pressure of CO2 afforded corresponding coumarins in good yield. Furthermore, isolation of the key alkenylpalladium intermediate via C-H bond cleavage was achieved. The reaction was proposed to undergo