Mechanistic Insights into the Reaction of Enantiomerically Pure Lithiosilanes and Electrophiles: Understanding the Differences between Aryl and Alkyl Halides
作者:Christian Däschlein、Simeon O. Bauer、Carsten Strohmann
DOI:10.1002/ejic.201000834
日期:2011.3
focus on product composition and enantiomeric ratios as a basis for a better understanding of ongoing mechanisms. Both parameters are strongly influenced by both the organic group and the corresponding halide of the used electrophile. Thus, high stereoselectivities and yields are only obtained if one distinct reaction mechanism dominates. In the case of aliphatic electrophiles, experimental and quantum
Synthesis of a Highly Enantiomerically Enriched Silagermane and Selective Cleavage of the Si−Ge Bond with Lithium
作者:Carsten Strohmann、Christian Däschlein
DOI:10.1021/om700848z
日期:2008.6.9
(R)-PhMe(CH2NC5H10)SiGeMe3, the first enantiomerically pure silagermane with stereoinformation at the silicon, was synthesized via a lithiosilane with retention of configuration. Further reaction with lithium resulted in unanticipated silicon−germanium bondcleavage to form PhMe(CH2NC5H10)SiLi, although the disilane (R)-PhMe(CH2NC5H10)SiSiMe3 undergoes silicon−phenylbondcleavage. A trapping reaction with p
(R)-PhMe(CH 2 NC 5 H 10)SiGeMe 3,是第一种对映体纯的在硅上具有立体信息的对映烷,是通过锂硫硅烷合成的,并保留了构型。尽管乙硅烷(R)-PhMe(CH 2 NC 5 H 10)SiSiMe 3与锂的进一步反应导致未预期的硅锗键断裂形成PhMe(CH 2 NC 5 H 10)SiLi经历硅-苯基键裂解。与五甲基氯乙硅烷的捕集反应在保留构型的情况下发生。在模型系统PhH 2 SiSiH 3和PhH 2 SiGeH 3上进行的DFT计算表明,硅元素键断裂是逐步解离的电子转移机理。
A Highly Enantiomerically Enriched Lithiosilane by Selective Cleavage of a Silicon–Phenyl Bond with Lithium
Synthesis of a highly enantiomerically enriched silyllithium compound
作者:Carsten Strohmann、Jan Hörnig、Dominik Auer
DOI:10.1039/b111687h
日期:2002.3.21
The highlyenantiomericallyenriched silyllithium compound lithiomethylphenyl(1-piperidinylmethyl)silane (4) reacts stereospecifically with chlorosilanes, but over a period of several hours slow racemization in solution at room temperature occurs, which can be suppressed by a transmetalation reaction with MgBr2(thf)4.