General and selective metal-free radical ?-C-H borylation of aliphatic amines

Despite recent developments, selective C(sp3)-H borylation of feed-stock amines remains a formidable challenge. Herein, we have developed a general, mild, and photoinduced transition-metal -and strong-base-free method for a-C(sp3)-H borylation of amines. This protocol features a regioselective 1,5-hydrogen atom transfer process to access key a-aminoalkyl radical intermediate using commercially available easy-to-install/remove iodobenzoyl radical translocating group. Remarkably, this general, efficient, and opera-tionally simple method allows activation of primary and secondary a-C-H sites of a broad range of acyclic and cyclic amines toward highly regio-and diastereo-selective syntheses of valuable a-amino-boronates. 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.

Automated summary

This study presents a general, mild, and photoinduced method for selective a-C(sp3)-H borylation of amines. The protocol allows activation of a broad range of acyclic and cyclic amines, enabling highly regio- and diastereoselective syntheses of valuable a-amino-boronates. The utility of this method has been demonstrated in late-stage borylation of structurally complex amines and formal C-H arylation reaction of amines. It is expected to find broad application in organic synthesis and drug discovery.