Harmonizing Visible-Light in Green Synthesis: Unrevealing the Brilliance of Metal-Free Cross-Coupling of Unsaturated Hydrocarbons for C−C Bonds Formation

Visible-light induced, photoredox catalysis has opened a wide range in the transformation of organic compounds in recent times. In synthetic organic chemistry HAT (hydrogen atom transfer) and SET (single electron transfer) mechanisms are a very noteworthy routes that has opened a window in favor of C−C single bond formations. Usually, a major role of unsaturated hydrocarbons is to participate in carbon-carbon bond formation as they carry reactive π-bond. Under visible-light, metal-free cross-coupling reactions are particularly favorable because of their atom economy, increased efficiency, and environmentally friendly procedures that result in the construction of C−C bonds. The review emphasizes the latest advancements of visible-light mediated, cross-coupling reactions of unsaturated hydrocarbons in metal-free conditions for constructing carbon-carbon single bonds.