Copper-Catalyzed Highly Efficient and Asymmetric Allylic C–H Oxidation of 3-Aryl-Substituted Terminal Alkenes

Asymmetric allylic C(sp³)-H oxidation of terminal alkenes provides a streamlined process for accessing allylic alcohols and their derivatives; however, it represents a long-standing challenge in the field for several decades. Herein, we disclosed a copper-catalyzed approach for the enantioselective allylic C(sp³)-H oxidation of terminal alkenes, facilitated by introducing a sterically bulky B₂Im(C₆F₅)₆ anion. Notably, a wide range of aryl-substituted terminal alkenes were used as limiting reagents, delivering various products with excellent enantioselectivity and regioselectivity (up to 99% ee, >20:1 b/l). Mechanistically, the bulky counteranion was found to be essential for achieving excellent enantioselective control and high catalytic efficiency.