Synthesis of unsymmetrical 1,2-bis(diorganochlorosilyl)ethanes
摘要:
Unsymmetrical 1,2-bis(diorganylsilyl)ethanes were synthesized by two procedures. Hydrosilylation of chloro(vinyl)silanes were used to obtain compounds of the general formula ClMe2SiCH2CH2SiRMeCl with different substituents (R = Et, Vin, Ph) on the silicon atom. Chlorodealkylation of 1,2-bis(trialkylsilyl)ethanes gave compounds of the general formula ClAlk(2)SiCH(2)CH(2)SiAlk(2)Cl (Alk = Me, Et, Pr). It is established that the latter reaction provides high yields only with Me- and Et-substituted compounds, whereas Pr-substituted products are formed in poor yields. The mechamism of this reaction based on quantum-chemical calculations is offered.
Silicon(II) Cation Cp*Si:<sup>+</sup>X<sup>–</sup>: A New Class of Efficient Catalysts in Organosilicon Chemistry
作者:Elke Fritz-Langhals
DOI:10.1021/acs.oprd.9b00260
日期:2019.11.15
The catalytic activity of the pentamethylcyclopentadienylsilicon(II) cation Cp*Si:+ was investigated. It was shown that Cp*Si:+ efficiently catalyzes reactions of technical relevance in organosiliconchemistry: Cp*Si:+ proved to be a very efficient nonmetallic catalyst for the hydrosilylation of olefins at low catalyst amounts of <0.01 mol % and for the Piers–Rubinsztajn reaction in order to make controlled
Trialkylsilanes readily undergo dehydrocondensation with acetylene and substituted acetylenes in the presence of the catalytic systems, H2PtCl6/iodine, lithium iodide or /trialkyliodosilanes, and so the monosubstitutedacetylenes HCCR (R = C4H9, C(CH3)3, CH2Cl, C6H5) smoothly afford the corresponding trialkyl(organylethynyl)silanes. In hexane or benzene the yield of the dehydrocondensation products
在催化体系,H 2 PtCl 6 /碘,碘化锂或/三烷基碘硅烷的存在下,三烷基硅烷很容易与乙炔和取代的乙炔进行脱氢缩合反应,因此单取代的乙炔HCCR(R = C 4 H 9,C(CH 3)3,CH 2 Cl,C 6 H 5)平稳地得到相应的三烷基(有机基乙炔基)硅烷。在己烷或苯中,脱氢缩合产物的产率为90%。三乙基硅烷与乙炔的脱氢产物为双(三乙基磺酰基)乙炔和1,2-双(三乙基甲硅烷基)乙烷。讨论了反应机理。
Ligands Make the Catalyst: Synthesis of Novel Functionalized Phosphines
Many catalytic active transition metal complexes contain phosphines as ligands which control decisively the activity and selectivity of the catalyst. Therefore synthetic methods which allow the preparation of highly functionalized phosphines are needed to match the increasing demands for higher activity and selectivity in catalytic processes. In this report we introduce a simple general new method