Rhodium(III)-Catalyzed<i>ortho</i>Alkenylation of<i>N</i>-Phenoxyacetamides with<i>N</i>-Tosylhydrazones or Diazoesters through CH Activation
作者:Fangdong Hu、Ying Xia、Fei Ye、Zhenxing Liu、Chen Ma、Yan Zhang、Jianbo Wang
DOI:10.1002/anie.201309650
日期:2014.1.27
A coupling reaction of N‐phenoxyacetamides with N‐tosylhydrazones or diazoestersthrough RhIII‐catalyzed CHactivation is reported. In this reaction, ortho‐alkenyl phenols were obtained in good yields and with excellent regio‐ and stereoselectivity. Rh–carbene migratory insertion is proposed as the key step in the reaction mechanism.
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