Light-Promoted Bromine-Radical-Mediated Selective Alkylation and Amination of Unactivated C(sp3)–H Bonds

Summary Substantial effort is currently being devoted to selective C(sp3)–H bond functionalization, and photocatalysis has presented enormous potential opportunities in this research field. Here, we developed a visible-light-induced functionalization of unactivated C(sp3)–H bonds via the synergistic effects of an organo-photoredox catalyst and a bromine-based hydrogen atom transfer agent. By applying CH2Br2 as both the solvent and the bromine radical source, the alkylation and amination of tertiary C(sp3)–H bonds were achieved in a highly selective fashion. This study represents the first example of selective activation of unactivated alkanes by bromine radicals in a catalytic and metal-free manner. Good reactivity was achieved by using a sealed microtubing reactor or by adding a proper amount of water. This highly selective C(sp3)–H functionalization protocol offers a new paradigm for the direct synthesis of valuable compounds from abundant alkane feedstocks in a convenient and green manner.