Abstract:Recently, the fabrication of organic compounds via functionalization of olefins has become one hotspot in organic synthesis. When choosing transition metal complexes with various types, crystal structures and multifunctional properties as catalysts, the reactions have high efficiency, high selectivity and low cost. This work summarized the progress in the functionalization of unactivated olefins via free radical reaction by use of transition metal salts and their complexes as catalysts in the past five years. The characteristic of the reaction is that olefins generate free radicals and react with other substrates or reagents in the presence of transition metal catalysts. Among them, catalysts with excellent catalytic properties contains not only complexes of precious metals such as rhodium, palladium and ruthenium, but also the salts and complexes of common metals, such as iron, nickel, copper and cobalt. These methods expand the research fields of functionalization of olefins, and provide new methods and ideas for organic chemists, and also offer new solutions for further industrial production.