Flavin‐Catalyzed Aerobic Oxidative C−C Bond Formation by Metal/Light‐Free Cross‐Dehydrogenative Coupling

Biomimetic flavin catalysts enable green and selective aerobic oxidative transformations. However, most previous studies tended to focus on reproducing the enzymatic function of flavin monooxygenase, thereby limiting the applications of flavin catalysts to oxygen‐atom transfer reactions. We herein report a cross‐dehydrogenative coupling (CDC) between the sp3 C−H bond of tetrahydroisoquinolines and the sp3 and sp2 C−H bonds of carbon nucleophiles, such as α‐methylene carbonyl compounds, nitromethane, and indoles, for C−C bond formation promoted by flavin catalysts. Flavin catalysis enables the oxidative C−H activation of tetrahydroisoquinolines and the efficient activation of molecular oxygen (1 atm) under mild and metal/light‐free conditions, thus facilitating a green aerobic CDC that generates benign water as the sole by‐product.