Selective functionalization of benzylic C(sp3)–H bonds to synthesize complex molecules

Functionalization of the benzylic C(sp3)–H bond has become a compelling and robust tool to speed up pre-clinical research for “lead discovery.” Besides bring frequently utilizated to construct complex molecules in total synthesis, this emerging strategy of benzylic C(sp3)–H bond functionalization has facilitated site-selective modifications of complex molecules. Here, we have summarized recent benzylic C(sp3)–H bond functionalization applications for synthesizing complex molecules. We have carefully addressed recent applications in this topic, ranging from the site-selective modifications using benzylic C–H bond functionalization to the total synthesis of natural products. This review will recount the formation and application of new C–C, C–O, C–N, and C–X (X = halogens, sulfur, etc.) bonds to provide a clear blueprint for and deep insight into the functionalization of benzylic C–H bonds.