title: Computational study on the reaction mechanism of hydrosilylation of carbonyls catalyzed by high-valent rhenium(V)-di-oxo complexes.
abstract: Density functional theory (DFT) calculations have been performed to elucidate the reaction mechanism of hydrosilylation of carbonyl compounds catalyzed by high-valent rhenium(V)-di-oxo complexes ReO2I(PR3)2 (R = Me, Ph). The calculations suggest that the most favorable mechanism involves the rate-determining dissociative [2 + 2] addition of the Si-H bond across a Re=O bond to form a Re(V) hydrido siloxy intermediate; this is followed by carbonyl coordination, reduction of the carbonyl, rearrangement, and final intramolecular nucleophilic attack from the alkoxy group to the silyl center (dissociative retro-[2 + 2] addition). It was also found that the additional oxo ligand in the ReO2I(PR3)2 complexes promotes the [2 + 2] addition across the rhenium-oxo bond both kinetically and thermodynamically, as compared to the neutral rhenium(V)-mono-oxo complex ReOCl3(PMe3)2. The effect of different silanes on the [2 + 2] addition barriers is also studied.
authors.affiliation: Department of Chemistry and Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Lung Wa
authors.initials: LW
authors.lastname: Chung
authors.forename: Hung Gai
authors.initials: HG
authors.lastname: Lee
authors.forename: Zhenyang
authors.initials: Z
authors.lastname: Lin
authors.forename: Yun-Dong
authors.initials: YD
authors.lastname: Wu
mesh_terms: D002384:Catalysis; D003198:Computer Simulation; D006859:Hydrogen / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry
chemical_list: D008024:Ligands; D012821:Silanes; D012211:Rhenium; D006859:Hydrogen; D010100:Oxygen; D012825:Silicon