16546-47-7Relevant academic research and scientific papers
Substituent effects on the reactivity of the silicon-carbon double bond. Resonance, inductive, and steric effects of substituents at silicon on the reactivity of simple 1-methylsilenes
Leigh, William J.,Boukherroub, Rabah,Kerst, Corinna
, p. 9504 - 9512 (2007/10/03)
The reactivities of a series of substituted 1-methylsilenes RMeSi=CH2 (R = H, methyl, ethyl, t-butyl, vinyl, ethynyl, phenyl, trimethylsilyl, and trimethylsilymethyl) in hydrocarbon solvents have been investigated by far- UV (193-nm) laser flash photolysis techniques, using the corresponding 1- methylsilacyclobutane derivatives as silene precursors. Each of these silacyclobutanes yields ethylene and the corresponding silene, which can be trapped as the alkoxysilane RSiMe2OR' cleanly upon 193- or 214-nm photolysis in solution in the presence of aliphatic alcohols. UV absorption spectra and absolute rate constants for reaction of the silenes with methanol, ethanol, and t-butyl alcohol have been determined in hexane solution at 23°C. The rate constants vary from a low 3 x 107 M-1 s-1 for reaction of 1- methyl-1-trimethylsilylsilene with t-BuOH to a high of 1 x 1010 M-1 s- 1 for reaction of 1-ethynyl-1-methylsilene with MeOH. In several cases, rate constants have been determined for addition of the deuterated alcohols, and for addition of methanol over the 0-55°C range. Invariably, small primary deuterium kinetic isotope effects and negative Arrhenius activation energies are observed. These characteristics are consistent with a mechanism involving reversible formation of a silene-alcohol complex which collapses to alkoxysilane by unimolecular proton transfer from oxygen to carbon. Silene reactivity increases with increasing resonance electron-donating and inductive electron-withdrawing ability of the substituents at silicon and is significantly affected by steric effects within this series of compounds. This is suggested to be due to a combination of effects on both the degree of electrophilicity at silicon (affecting the rate constants for formation and reversion of the complex) and nucleophilicity at carbon (affecting the partitioning of the complex between product and free reactants). Two 1- methyl-1-alkoxysilacyclobutanes were also investigated, but proved to be inert to 193-nm photolysis.
Alkoxylation of C-chlorovinylsilanes
Lakhtin, V. G.,Ryabkov, V. L.,Polyakova, M. V.,Nosova, V. M.,Kisin, A. V.,Chernyshev, E. A.
, p. 718 - 723 (2007/10/02)
The alkoxylation and isopropylideneiminoxylation of C-chlorovinylmethylchlorosilanes with various alcohols and acetone oxime were investigated.A series of new C-chlorovinylmethylalkoxy- and isopropylideneiminoxysilanes was characterized by IR and new 1H NMR spectra.The effect of the number of chlorine atoms in C-chlorovinylmethylchlorosilanes on their reactivity in these reactions was determined. - Key words: C-chlorovinylmethylchlorosilanes, etherification; C-chlorovinylmethylalkoxysilanes, alcohols, IR spectra; 1H NMR spectra.
THE BEHAVIOR OF ALKOXIDES WITH ALLYL(CHLOROMETHYL)DIMETHYLSILANES AND (CHLOROMETHYL)DIMETHYLVINYLSILANE; THE ABILITIES OF ALLYL AND VINYL GROUPS TO MIGRATE FROM PENTACOORDINATE SILICON
Sans, E. A.,Shechter, H.
, p. 1119 - 1122 (2007/10/02)
Sodium methoxide in tetrahydrofuran attacks silicon in allyl(chloromethyl)-dimethylsilane and in (chloromethyl)dimethylvinylsilane with displacement of chloride and 1,2-migration of the allyl and the vinyl groups to give 1-(3-butenyl)methoxydimethylsilane and allylmethoxydimethylsilane.
LE PROBLEME DE LA CONJUGAISON A TRAVERS UN ATOME DE SILICIUM ?-LIE DANS LES SYSTEMES SILA-2 BUTADIENIQUES
Bertrand, G.,Manuel, G.,Mazerolles, P.,Trinquier, G.
, p. 2875 - 2880 (2007/10/02)
The chemical behaviour of sila-2 butadienes, formed as transient intermediates either by thermolysis or by photolysis of various 1-vinylsilacyclobutanes, was studied with respect to hydroxylated compounds of different pKa values.Two mechanisms can explain the nature of the products obtained on the co-thermolysis of the cyclic compounds with phenol, one with 1-silacyclobut-1-ene intermediate and the other involving an allylic silicenium cation.In both hypothetical mechanisms, the 2-silabutadienes behave as a conjugated system since they lead either to cycloaddition or to (1,2)- and (1,4)-electrophilic addition.This evidence for a conjugation phenomenon through a silicon atom is supported by the calculation of the delocalisation energies of butadiene and 2-silabutadiene.
