Functionalization of C-H Bonds by Photoredox Catalysis

Visible-light photoredox catalysis has been successfully used in the functionalization of inert C-H bonds including C(sp(2))-H bonds of arenes and C(sp(3))-H bonds of aliphatic compounds over the past decade. These transformations are typically promoted by the process of single-electron-transfer (SET) between substrates and photo-excited photocatalyst upon visible light irradiation (household bulbs or LEDs). Compared with other synthetic strategies, such as the transition-metal catalysis and traditional radical reactions, visible-light photoredox approach has distinct advantages in terms of operational simplicity and practicability. Versatile direct functionalization of inert C(sp(2))-H and C(sp(3))-H bonds including alkylation, trifluoromethylation, arylation and amidation, has been achieved using this practical strategy.