Enantioselective Nickel-Catalyzed Denitrogenative Transannulation En Route to N-N Atropisomers.

Nickel-catalyzed transannulation reactions triggered by the extrusion of small gaseous molecules have emerged as a powerful strategy for the efficient construction of heterocyclic compounds. However, their use in asymmetric synthesis remains challenging because of the difficulty in controlling stereo- and regioselectivity. Herein, we report the first nickel-catalyzed asymmetric synthesis of N-N atropisomers by the denitrogenative transannulation of benzotriazones with alkynes. A broad range of N-N atropisomers was obtained with excellent regio- and enantioselectivity under mild conditions. Moreover, density functional theory (DFT) calculations provided insights into the nickel-catalyzed reaction mechanism and enantioselectivity control.