Transmetallation of organotransition metal complexes: Its relevance to mechanism of homogeneous catalytic reactions

Abstract

Transmetallation, generating organotransition metal species from alkylating reagent and metal complexes, plays important roles in many synthetic organic reactions catalyzed by transition metal complexes. This article describes recent progress in mechanistic study on the transmetallation and in elucidation of its relevance to synthetic organic reactions catalyzed by transition metal complexes. Pd complex catalyzed cross-coupling reactions of aromatic halides with organomagnesium and organotin reagents and with terminal alkynes involve transmetallation of alkyl and alkynyl group from the non -transition or transition metal compounds to Pd complexes. Ni(0) complex promoted dehalogenative condensation of aryl halides in DMF occurs via disproportionation of bromo(aryl)nickel(II) complexes to form diarylnickel complex which is responsible for reductive elimination of biaryls. Mechanisms of isomreization between cis- and trans-diarylpalladium complexes having auxiliary thioether ligand and of conproportionation of diorgano- and dichloro-complexes of group 10 metals are discussed.