Cobalt(II)-Catalyzed Activation of C(sp3)–H Bonds: Organic Oxidant Enabled Selective Functionalization

Herein we develop a new "cobalt(II)/organic oxidant" catalytic system for the selective activation of 1°, 2°, and 3° C(sp3)–H bonds to construct C–N and C–O bonds, respectively. The method highlights the use of an organic compound (TsNHOPiv or its analogues) as an emerging oxidant and thus provides a flexible strategy for the preparation of indoline and benzoxazine derivatives. Attractive advantages of this cobalt catalysis include simple operation, low cost, mild conditions, and broad substrate scope. Furthermore, a catalytically competent hydroxylamine-chelated organometallic Co(III)species was synthesized, thus providing deep insights into the catalytic mechanism.