Photosynthetic Fixation of CO2 in Alkenes by Heterogeneous Photoredox Catalysis with Visible Light

Abstract Light‐driven fixation of CO 2 in organics has emerged as an appealing alternative for the synthesis of value‐added fine chemicals. Challenges remain in the transformation of CO 2 as well as product selectivity due to its thermodynamic stability and kinetic inertness. Here we develop a boron carbonitride (BCN) with the abundant terminal B/N defects around the mesoporous walls, which essentially enhances surface active sites as well as charge transfer kinetics, boosting the overall rate of CO 2 adsorption and activation. In this protocol, anti‐Markovnikov hydrocarboxylation of alkenes with CO 2 to an extended carbon chain is achieved with good functional group tolerance and specific regioselectivity under visible‐light irradiation. The mechanistic studies demonstrate the formation of CO 2 radical anion intermediate on defective boron carbonitride, leading to the anti‐Markovnikov carboxylation. Gram‐scale reaction, late‐stage carboxylation of natural products and synthesis of anti‐diabetic GPR40 agonists reveal the utility of this method. This study sheds new insight on the design and application of metal‐free semiconductors for the conversion of CO 2 in an atom‐economic and sustainable manner.