Regio- and Stereoselective Synthesis of Multisubstituted Vinylsilanes via Zirconacycles†
摘要:
A series of novel multisubstituted vinylsilanes are prepared regio- and stereoselectively by carbozirconation of various alkynylsilanes through zirconacycles such as zirconacyclopropenes and zirconacyclopentenes and the subsequent transformation of the formed alkenylzirconocene complexes.
Regio- and Stereoselective Synthesis of Multisubstituted Vinylsilanes via Zirconacycles†
摘要:
A series of novel multisubstituted vinylsilanes are prepared regio- and stereoselectively by carbozirconation of various alkynylsilanes through zirconacycles such as zirconacyclopropenes and zirconacyclopentenes and the subsequent transformation of the formed alkenylzirconocene complexes.
cis-alkynyl(silyl)platinum(II) complexes was prepared via the chemoselective C(sp)–Si bond cleavage of alkynylsilanes by a platinum(0) complex ligated with the P–N hemilabile bidentateligand. The coordination of the triple bond to the platinum center triggers selective C(sp)–Si bond cleavage. Hammett plots of the 31P1H} NMR spectroscopic properties (δ and J values) reflect an electronic effect on platinum(II)
一系列顺式-炔基(甲硅烷基)铂(II)配合物是通过将炔基硅烷的化学选择性C(sp)-Si键与与P-N半不稳定双齿配体连接的铂(0)配合物裂解而制备的。三键与铂中心的配位会触发选择性的C(sp)-Si键裂解。31 P 1 H} NMR光谱特性(δ和J值)的哈米特图反映了对铂(II)配合物的电子效应;芳基乙炔基的反式取代基会受到影响,但顺式位置的甲硅烷基不会受到影响,如29 Si 11 H NMR。相比之下,哈米特图表明,富含电子的炔基硅烷可加速C(sp)-Si键的裂解速率,这与在催化交叉偶联反应中通常观察到的芳基卤化物向过渡金属的普通氧化加成相反。DFT计算表明,中间体和过渡态被富含电子的炔基硅烷稳定,并且五元半不稳定的PN配体是必不可少的,其中通过解离产生了反应性电子缺陷的14电子铂(0)物种。氮,导致单齿膦配位。富电子的炔基硅烷可以减少从铂中心到配体的π返配,从而加速了更不稳定的氮的离解。
Regio- and Stereoselective Synthesis of Multisubstituted Vinylsilanes via Zirconacycles<sup>†</sup>
A series of novel multisubstituted vinylsilanes are prepared regio- and stereoselectively by carbozirconation of various alkynylsilanes through zirconacycles such as zirconacyclopropenes and zirconacyclopentenes and the subsequent transformation of the formed alkenylzirconocene complexes.