754-05-2Relevant articles and documents
Radiolytic silylation of alkenes and alkynes by gaseous R3Si+ ions. Stereochemical evidence for the β-silyl effect
Chiavarino, Barbara,Crestoni, Maria Elisa,Fornarini, Simonetta
, p. 1523 - 1527 (1998)
Carbocation intermediate stabilized by a β silyl group have been characterized using the silylation of alkenes by R3Si+ ions as a route of formation. Neutral silylated products have been obtained from the reaction of R3Si+ ions, generated in a gaseous medium at atmospheric pressure by a radiolytic technique, with selected alkenes, alkynes, and allene, thereby indicating the occurrence of electrophilic silylation. Notable fectures of the charged silylated intermediates emerge from the isomeric product distribution. The silylation of cis- and trans-2-butene shows a high degree of retention of configuration, as expected if a bridged species (I) were the reaction intermediate. Alternatively, the intermediacy of an open structure (II), whereby C-C bond rotation is inhibited by the hyperconjugative interaction between the β silyl group and the vacant up orbital, should be inferred. The charged intermediates from the silylation of alkenes and alkynes are found to be unreactive toward conceivable isomerizations to more stable species, such as the ones bearing the positive charge of silicon. Stereoelectronic factors affect the deprotonation of the silylated intermediates, which may involves loss of the proton either the α or the γ position with respect to the silylated carbon. A comparison of the reactivity of alkenes and alkynes in the cationic silylation reaction is presented.
Trimethylsilylacetylene synthesis process
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Paragraph 0021, (2021/01/11)
The invention discloses a process route for synthesizing trimethylsilylacetylene, which comprises the following steps of: generating trimethylchlorosilylethylene by taking ethylene bromide and trimethylchlorosilane as initial raw materials through a Grignard method, and forming 1-bromo trimethylchlorosilylethylene under the action of alkali through a bromination reagent; and removing monomolecularhydrogen bromide under the action of strong alkali to generate trimethylsilylacetylene. Compared with the traditional process, the process route has the advantages that the use of gas acetylene is avoided, the risk is reduced, the safety is improved, the used raw materials are easily available, the operation is easy, the safety and the environmental protection are realized, and the industrial production can be realized.
Vanadium-Catalyzed Cross Metathesis: Limitations and Implications for Future Catalyst Design
Farrell, Wesley S.
supporting information, p. 3481 - 3485 (2019/11/13)
Self-metathesis of terminal olefins using vanadium(V) alkylidenes is presented. Under various reaction conditions, incomplete conversion is observed due to decomposition of the metallocyclobutane intermediate via β-hydride elimination. The activity was observed to decline when a more electron withdrawing, less sterically bulky ligand was used, in contrast to trends observed in ring-opening metathesis polymerization with vanadium catalysts. These results provide insight into the current limitations of olefin metathesis with vanadium catalysts, as well as guidance for catalyst development.
Cobalt-catalyzed hydrosilation/hydrogen-transfer cascade reaction: A new route to silyl enol ethers
Lyons, Thomas W.,Brookhart, Maurice
supporting information, p. 10124 - 10127 (2013/09/02)
Capitalizing on cobalt: A new route to silyl enol ethers employing a Co-catalyzed cascade reaction featuring a tandem hydrosilation/hydrogen-transfer reaction is reported. The low catalyst loading, mild reaction conditions, and unique η2-silane resting state showcase the impressive utility of this seldom used transition-metal catalyst in C-H activation reactions (see scheme; VTMS = vinyltrimethylsilane; Cp* = 1,2,3,4,5- pentamethylcyclopentadiene). Copyright
