Functionalization reactions of styrene and styrene derivatives.

C(sp3)-H bonds are ubiquitous in organic molecules, and their direct functionalization has garnered extensive attention and achieved remarkable progress in recent years. The direct functionalization of simple styrene, which involves incorporating functional groups into the carbon-carbon double bond, holds particular significance for organic synthesis due to its wide-ranging applications. Radical functionalization is especially attractive as it enables the rapid and convenient transformation of simple styrene into complex molecules. Moreover, radical di-functionalization allows for the addition of various carbon-centered and even heteroatom-centered radicals to styrene. This review provides a comprehensive overview of the direct mono-functionalization of styrene and its derivatives, as well as di-functionalization reactions of styrene derivatives via radical reactions. It focuses on reaction patterns, mechanisms, and potential applications in synthetic chemistry. Special attention is given to the di-functionalization reactions of styrene derivatives with solvent molecules such as alcohols, ketones, nitriles, ethers, and thioethers, which have been named Wang reactions.