General and Selective Metal-Free Radical α-C-H Borylation of Aliphatic Amines

Despite recent developments, selective C(sp³)-H borylation of feedstock amines remains a formidable challenge. Herein, we have developed a general, mild, and photoinduced transition metal- and strong base-free method for α-C(sp³)-H borylation of amines. This protocol features a regioselective 1,5-hydrogen atom transfer process to access key α-aminoalkyl radical intermediate using commercially available easy-to-install/remove iodobenzoyl radical translocating group. Remarkably, this general, efficient, and operationally simple method allows activation of primary and secondary α-C-H sites of a broad range of acyclic and cyclic amines toward highly regio- and diastereoselective synthesis of valuable α-aminoboronates. Utility of this protocol has been demonstrated by its employment in late-stage borylation of structurally complex amines and formal C-H arylation reaction of amines. Thus, it is expected that this operationally simple, general, and practical method will find broad application in organic synthesis and drug discovery.