Chemoselective Amination of Propargylic C(sp³)H Bonds by Cobalt(II)‐Based Metalloradical Catalysis

Highly chemoselective intramolecular amination of propargylic C(sp(3))-H bonds has been demonstrated for N-bishomopropargylic sulfamoyl azides through cobalt(II)-based metalloradical catalysis. Supported by D(2h)-symmetric amidoporphyrin ligand 3,5-Di(t)Bu-IbuPhyrin, the cobalt(II)-catalyzed C-H amination proceeds effectively under neutral and nonoxidative conditions without the need of any additives, and generates N2 as the only byproduct. The metalloradical amination is suitable for both secondary and tertiary propargylic C-H substrates with an unusually high degree of functional-group tolerance, thus providing a direct method for high-yielding synthesis of functionalized propargylamine derivatives.