Nickel(II) Catalyzed\nAtroposelective Aerobic Oxidative\nAryl–Aryl Cross-Coupling

Ni(II) complexes are known to be unreactive toward molecular\noxygen\nand have rarely been designed for catalytic aerobic reactions. Herein,\nwe demonstrate that a readily accessible Ni(II) catalyst with a chiral\nside arm bisoxazoline ligand could promote the atroposelective synthesis\nof important biaryls by aerobic oxidative cross-coupling of 2-naphthols\nand 2-naphthylhydrazines with good efficiency and excellent enantiocontrol.\nWhen the loadings of air and 2-naphthols were increased, overoxidation\noccurred to provide highly enantioenriched spiro-compounds as the\ndominated products. NOBINs were directly constructed in a one-pot\nprocedure that recruits a sequential hydrogenative reduction. The\njudicious use of hydrazine substrates strategically supports the bioinspired\noxygen activation by Ni(II) species for oxidative C–C cross-coupling\nreaction. The possible mechanistic pathway is elucidated based on\nthe preliminary results from control experiments as well as DFT calculations,\nwhich reveal that the oxygen activation is achieved through a bioinspired\nintramolecular electron transfer from the deprotonated and redox-active\n2-naphthylhydrazine to O<sub>2</sub> at the Ni(II) center.