Dual Activity of Ruthenium Complexes in Olefin Metathesis and Radical Reactions

Abstract

Attempt to understand how metal complexes mediate the formation of carbon-carbon bonds is a major theme in organometallic chemistry. A much studied example among the carboncarbon bond-forming reactions is that of metal carbene bonds with olefins, a reaction leading to different products, depending on the metal, its oxidation state and its ancillary ligands [1]. On the other hand, radical methods are maybe the most powerful tools for carbon-carbon bond formation. Radical polymerisation [2] is one of the most important methods for synthesising polymers with nearly 50 % of synthetic polymers prepared through radical processes [3]. In pharmaceutical and fine organic synthesis free radical reactions, particularly cyclisations, have been extensively studied over the past twenty years. In recent years, transition metal mediated free radical processes have gained in importance. In particular the Kharasch addition to olefins such as atom transfer radical addition (ATRA) and atom transfer radical cyclisation (ATRC) and its extension to olefin polymerisation known as atom transfer radical polymerisation (ATRP) have been reported with a wide range of metal catalysts.