Synthesis of 1,2-Bis silyl -Alkenes

Vinylsilanes are important alkene derivatives that have been widely used as synthetic intermediates, monomers for copolymer plastics, and coupling agents for hybrid silicon materials (1). Transition-metal-catalyzed hydrosilylation and bis-silylation of alkynes represent the most straightforward and atom-economic routes to vinylsilanes (2). The original reports on palladium-catalyzed bis-silylation of alkynes with disilanes were published by Kumada and Sakurai (3). 

Reactions of silylenes with alkynes present an alternative approach for the silylation of alkynes without the aid of transition-metal catalysts (4). The bis-silylation reaction has been accomplished in a stereospecific manner via a 1,4-silyl migration with the easily available NHC-stabilized silylaminosilylene Ar SiMe3)N(Cl)Si- hPr) (Ar = 2,6-iPr2C6H3, hPr = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) under metal-free conditions (5), representing the first successful approach for the selective bis-silylation of alkynes with a donor-supported silylene as the silylation reagent. Furthermore, the alcoholysis of these bis-silylated alkenes gave trimethoxylsilyl-substituted alkenes. 

R = Electron-withdrawing groups such as COOR and phenyi groups Ar — 2,6-/Pr2C0H3 

Three-necked bottle, constant pressure funnel, magnetic stirrer, 

Claisen distilling head, round-bottom flask, low-temperature reactor, safety glasses, laboratory coat, and protective gloves. 

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