title: Mechanism of intermolecular hydroacylation of vinylsilanes catalyzed by a rhodium(I) olefin complex: a DFT study.
abstract: Density functional theory (DFT) was used to investigate the Rh(I)-catalyzed intermolecular hydroacylation of vinylsilane with benzaldehyde. All intermediates and transition states were optimized completely at the B3LYP/6-31G(d,p) level (LANL2DZ(f) for Rh). Calculations indicated that Rh(I)-catalyzed intermolecular hydroacylation is exergonic, and the total free energy released is -110 kJ mol(-1). Rh(I)-catalyzed intermolecular hydroacylation mainly involves the active catalyst CA2, rhodium-alkene-benzaldehyde complex M1, rhodium-alkene-hydrogen-acyl complex M2, rhodium-alkyl-acyl complex M3, rhodium-alkyl-carbonyl-phenyl complex M4, rhodium-acyl-phenyl complex M5, and rhodium-ketone complex M6. The reaction pathway CA2 + R2 → M1b → T1b → M2b → T2b1 → M3b1 → T4b → M4b → T5b → M5b → T6b → M6b → P2 is the most favorable among all reaction channels of Rh(I)-catalyzed intermolecular hydroacylation. The reductive elimination reaction is the rate-determining step for this pathway, and the dominant product predicted theoretically is the linear ketone, which is consistent with Brookhart's experiments. Solvation has a significant effect, and it greatly decreases the free energies of all species. The use of the ligand Cp' (Cp' = C(5)Me(4)CF(3)) decreased the free energies in general, and in this case the rate-determining step was again the reductive elimination reaction.
authors.affiliation: College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Qingxi
authors.initials: Q
authors.lastname: Meng
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.forename: Ming
authors.initials: M
authors.lastname: Li
mesh_terms: D000215:Acylation; D000475:Alkenes; D002384:Catalysis; D008958:Models, Molecular; D012238:Rhodium / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry
chemical_list: D000475:Alkenes; D012821:Silanes; D014753:Vinyl Compounds; D012238:Rhodium