Atroposelective De Novo Access to Biaryls via Nickel-Catalyzed C–C Activation of Benzocyclobutenols: Aryl Sources Powered by Dual Ring Scissions

The C–C bond activation allows direct reconstruction of organic frameworks. However, atroposelective catalysis via C–C activation has been limited to the employment of a substrate with a preinstalled axis. Described here is the Ni(0)/PYBOX-catalyzed de novo construction of chiral axis via the asymmetric C–C coupling of benzotriazinones and benzocyclobutenols, which proceeded under mild conditions with high enantioselectivity to give biaryls with multifunctional groups. The reactivity was enabled by N–N and C–C activations, with dual ring scission as a driving force. A combination of experimental and computational studies revealed details of the catalytic mechanism. Key steps include the N–N oxidative addition of the benzotriazinones to give a stable nickelacycle. Subsequent β-carbon elimination of the ligated benzocyclobutenol is turnover-limiting, and the product is delivered from the enantio-determining C–C reductive elimination.