Synthesis of and catalytic nitrile hydration by a cationic tris(μ-hydroxo)diruthenium(II) complex having PMe3 ligands

Abstract

COD = cyclooctadiene (C8H12), COT = cyclooctatriene (C8H12), Cp* = pentamethylcyclopentadienyl (C5Me5-). DMPE = 1,2-bis(dimethylphosphino)ethane (Me2PC2H4PMe2), DEPE = 1,2bis(diethylphosphino)ethane (Et2PC2H4PEt2). KEYWORDS. CO Bond activation, Tris(hydroxo)diruthenium(II), Hydration of nitriles DEDICATION. This article celebrates Martin A. Bennett's 80 th birthday and numerous path breaking contributions to organometallic chemistry.

Hydration of Aliphatic Nitriles Catalyzed by an Osmium Polyhydride: Evidence for an Alternative Mechanism

“…Aromatic nitriles have been mainly used in a ratio of about 2:1 with respect to aliphatic ones (Table S1). The reactions have been in an overwhelming preponderance performed in water as the solvent and, to a lesser extent, in alcohols, ethers, or their mixtures with water . Although complexes of metals of groups 6 , and 8–11 ,,,,,, have proven to be active for nitrile hydration reactions, more than half of the reported catalysts are ruthenium compounds, ,,− ,,,,,, and the vast majority of them bear specific ligands that enhance the solubility of the complex in water by means of the formation of hydrogen bonds with solvent molecules. ,,,,,,,,, The improvement of catalysts and reaction conditions have mainly been based on empirical data obtained from trial-and-error methods.…”

“…The reactions have been in an overwhelming preponderance performed in water as the solvent and, to a lesser extent, in alcohols, ethers, or their mixtures with water . Although complexes of metals of groups 6 , and 8–11 ,,,,,, have proven to be active for nitrile hydration reactions, more than half of the reported catalysts are ruthenium compounds, ,,− ,,,,,, and the vast majority of them bear specific ligands that enhance the solubility of the complex in water by means of the formation of hydrogen bonds with solvent molecules. ,,,,,,,,, The improvement of catalysts and reaction conditions have mainly been based on empirical data obtained from trial-and-error methods. Kinetic analysis of the reactions, , isolation of the reaction intermediates, ,, and a density functional theory (DFT) study of the catalysis ,, the three legs of the mechanistic investigationhave received scarce attention.…”

Ni(0)-promoted activation of Csp2–H and Csp2–O bonds

“… 9 In general, when acyclic vinyl ethers react with transition metal complexes, metal alkoxide species are the major product, concomitant with loss of alkene. 35 Recently, the Fujita group reported that [(η 5 -C 5 Me 5 Ir) 2 (μ-bis(dimethylphosphino)methane) (μ-H)][OTf] reacts with ethyl vinyl ether to give a dimeric Ir complex featuring a bridging vinyl ligand. 36 Conveniently, the vinyl complex 5 can be prepared in >93% yield via the reduction of ( acri PNP)NiCl with a magnesium powder in the presence of ethyl vinyl ether, see ESI.…”

Hydroxide complexes of the late transition metals: Organometallic chemistry and catalysis

“…12,13 [(Ru(PMe3)3)2(µ-OH)3] + has been employed in E-selective alkyne dimerization reactions 14 and in nitrile hydration. 15 Ruthenium hydroxide intermediates have been implicated in other nitrile hydration reactions, 16 and in the dehydrogenation of methanol. 17 Several dimeric ruthenium complexes with bridging hydroxide ligands were prepared from the reaction of the corresponding chloride complexes with aqueous base, and were applied in the reduction of alkynes using alcohols as the hydrogen source (Scheme 3).…”