Transition-Metal-Free Site-Selective β- and γ-C-H Borylation of Aliphatic Amines

A mild photoinduced transition metal-free method for β- and γ-C(sp³)-H borylation of amines has been developed. This protocol features a regioselective intramolecular hydrogen atom transfer (HAT) process to access key amino alkyl radical intermediate employing commercially available, installable/removable iodoaryl tethers. Notably, this method introduces a new iodopyridyl-based hydrogen atom transferring group for abstraction of previously elusive β-C-H bonds of amines. Remarkably, this general and operationally simple method allows activation of primary, secondary, and tertiary C-H sites of a broad range of acyclic and cyclic secondary amines and offers a complementary platform toward regioselective and diastereoselective syntheses of valuable β- and γ-amino boronates. Utility of this protocol has been demonstrated through formal C-H oxidation reaction and other late-stage derivatizations of amines.