Ruthenium and osmium complexes in C-C bond-forming reactions by borrowing hydrogen catalysis

This review deals with the application of ruthenium and osmium complexes in C-C bond-forming reactions by borrowing hydrogen (BH) or hydrogen autotransfer (HA) catalysis, describing the considerable progress made over the years by these metal-complexes in the alpha-alkylation of ketones, beta-alkylation of secondary alcohols, C-alkylation of relatively inactivated substrates bearing fewer acidic alpha-hydrogens (acetonitriles, acetamides, esters, etc.) with alcohols, and in the formation of other C-C bonds using alcohols as substrates (or reactants). The results obtained in a process based on ruthenium- and osmium catalysed alcohol-unsaturate transfer hydrogenative C-C couplings are also included. Moreover, mechanistic aspects related to these reactions are discussed. (C) 2016 Elsevier B.V. All rights reserved.