Copper-Catalyzed Asymmetric C-H Sulfilimination of Arenes via HAT-Primed C-S Radical-Radical Coupling

As an important class of chiral-at-sulfur products, sulfilimines play an important role in diverse fields as functional molecules. Reported herein is the efficient synthesis of sulfilimines via oxidative C-H sulfilimination of (hetero)arenes with sulfenamides under copper catalysis. In particular, the sulfilimination of indoles and naphthols proceeded under mild conditions in excellent regio- and enantioselectivity with air or organic peroxide as the oxidant, and the configurational lability of the sulfilimine products further highlighted the challenge of this catalytic system. Experimental and computational mechanistic studies revealed a dual hydrogen atom transfer (HAT) pathway, and the C-S formation occurs via an outer-sphere HAT-primed radical-radical coupling with concerted arene HAT and C-S bonding in an eight-membered ring transition state.