Catalytic Enantioselective [4+1]-Annulation of Carboxylic Acids with Cyclopropenes

An efficient asymmetric synthesis of 3-vinylphthalides has been accomplished through rhodium-catalyzed [4+1]-annulation of arylcarboxylic acids with cyclopropenes involving C-H bond functionalization. The method exhibited excellent compatibility for various functional groups and offered diverse substituted 3-vinylphthalides in excellent yield and enantioselectivity. Synthetic application and control experiments were also performed to demonstrate the utility and understand the reaction pathway.