title: Ligand-controlled remarkable regio- and stereodivergence in intermolecular hydrosilylation of internal alkynes: experimental and theoretical studies.
abstract: The first highly efficient ligand-controlled regio- and stereodivergent intermolecular hydrosilylations of internal alkynes have been disclosed. Cationic ruthenium complexes [Cp*Ru(MeCN)3](+) and [CpRu(MeCN)3](+) have been demonstrated to catalyze intermolecular hydrosilylations of silyl alkynes to form a range of vinyldisilanes with excellent but opposite regio- and stereoselectivity, with the former being α anti addition and the latter β syn addition. The use of a silyl masking group not only provides sufficient steric bulk for high selectivity but also leads to versatile product derivatizations toward a variety of useful building blocks. DFT calculations suggest that the reactions proceed by a mechanism that involves oxidative hydrometalation, isomerization, and reductive silyl migration. The energetics of the transition states and intermediates varies dramatically with the catalyst ligand (Cp* and Cp). Theoretical studies combined with experimental evidence confirm that steric effect plays a critical role in governing the regio- and stereoselectivity, and the interplay between the substituent in the alkyne (e.g., silyl group) and the ligand ultimately determines the observed remarkable regio- and stereodivergence.
authors: Department of Chemistry, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong SAR, China.
authors: Shengtao
authors: S
authors: Ding
authors: Li-Juan
authors: LJ
authors: Song
authors: Lung Wa
authors: LW
authors: Chung
authors: Xinhao
authors: X
authors: Zhang
authors: Jianwei
authors: J
authors: Sun
authors: Yun-Dong
authors: YD
authors: Wu
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012428:Ruthenium / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D056831:Coordination Complexes; D008024:Ligands; D012821:Silanes; D012428:Ruthenium