Metal‐Free Cross‐Dehydrogenative Coupling (CDC): Molecular Iodine as a Versatile Catalyst/Reagent for CDC Reactions

Abstract The development of ecofriendly methods for carbon–carbon (C−C) and carbon–heteroatom (C−Het) bond formation is of great significance in modern‐day research. Metal‐free cross‐dehydrogenative coupling (CDC) has emerged as an important tool for organic and medicinal chemists as a means to form C−C and C−Het bonds, as it is atom economical and more efficient and greener than transition‐metal catalyzed CDC reactions. Molecular iodine (I 2 ) is recognized as an inexpensive, environmentally benign, and easy‐to‐handle catalyst or reagent to pursue CDCs under mild reaction conditions, with good regioselectivities and broad substrate compatibility. This review presents the recent developments of I 2 ‐catalyzed C−C, C−N, C−O, and C−S/C−Se bond‐forming reactions for the synthesis of various important organic molecules by cross‐dehydrogenative coupling.