A Metal-and Solvent-Free Bromination of Electron-Deficient Allyl and Benzyl C-H Bonds

Abstract

Bromination reactions of C(sp 3 )-H bonds at allylic and benzylic positions have been widely applied in the synthesis of pharmaceuticals and functional materials. However, traditional Wohl-Ziegler bromination reactions often involve harsh reaction conditions and afford low to moderate yields. In particular, direct bromination of electron-deficient allylic and benzylic C-H bonds has been rarely reported. Herein, we present an NHPI-catalyzed bromination method for electron-deficient allylic and benzylic C-H bonds. This method is metal-and solvent-free, exhibits high site selectivity and good yields, operates under mild conditions, and is operationally simple.