title: Activation of Ene-Diamido Samarium Methoxide with Hydrosilane for Selectively Catalytic Hydrosilylation of Alkenes and Polymerization of Styrene: an Experimental and Theoretical Mechanistic Study.
abstract: Samarium methoxide incorporating the ene-diamido ligand L(DME)Sm(μ-OMe)2Sm(DME)L (1; L = [DipNC(Me)C(Me)NDip](2-), Dip = 2,6-iPr2C6H3, and DME = 1,2-dimethoxyethane) has been prepared and structurally characterized. Complex 1 catalyzed the syndiospecific polymerization of styrene upon activation with phenylsilane and regioselective hydrosilylation of styrenes and nonactivated terminal alkenes. Unprecedented regioselectivity (>99.0%) for both types of alkenes has been achieved with the formation of Markovnikov and anti-Markovnikov products in high yields, respectively, whereas the polymerization of styrene resulted in the formation of syndiotactic silyl-capped oligostyrenes. The kinetic experiments and density functional theory calculations strongly support a samarium hydride intermediate generated by σ-bond metathesis of the Sm-OMe bond in 1 with PhSiH3. In addition, the observed regioselectvity for hydrosilylation and polymerization is consistent with the calculated energy profiles, which suggests that the bulky ene-diamido ligand and samarium hydride intermediate have important roles for regio- and stereoselectivity.
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Chaoyue
authors.initials: C
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Jinxi
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Hanmin
authors.initials: H
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Fengxin
authors.initials: F
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Xiufang
authors.initials: X
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300071, P. R. China.
authors.forename: Chunming
authors.initials: C
authors.lastname: Cui