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.