Photoinduced Hydrogen Atom Transfer Activation of Benzylic C−H Bonds Functionalization

Visible light, as an efficient and renewable resource, has gained significant attention in organic synthesis due to its mild, inexpensive, and environmentally friendly nature. Among the various photocatalytic processes, hydrogen atom transfer (HAT) has become a crucial mechanism for the activation of C−H bonds, with a particular focus on the functionalization of benzylic C(sp³)−H bonds. This review shows recent developments in the area of photoinduced HAT and its use in benzylic C−H bonds functionalization. We discuss halogen atom radicals, N‐centered radical, O‐centered radical, S‐centered radical and C‐centered radical in HAT processes, and influence on reaction selectivity and substrate versatility. The potential of photoinduced HAT to bypass the need for transition metal catalysts and directing groups positions it as a promising approach for constructing intricate organic molecules with high atom economy and sustainability. This review aims to offer a detailed summary of the current state of photoinduced HAT, providing insights into its potential uses in synthetic chemistry.