Kinetic Study on the Reaction of (Arylthio)trimethylsilanes with Phenacyl Bromide Giving Aryl Phenacyl Sulfides and Bromotrimethylsilane
作者:Seizi Kozuka、Tetsuji Higashino、Takuro Kitamura
DOI:10.1246/bcsj.54.1420
日期:1981.5
A kinetic study has been conducted on the reactions of (arylthio)trimethylsilanes with phenacyl bromide giving aryl phenacyl sulfides and bromotrimethylsilane. Remarkably large positive substituent effect (ρ=+2.2) and large negative entropy of activation were observed for the reaction. A mechanism involving 5-coordinated silicon intermediate prior to the rate-determining heterolysis of the Si–S bond
In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
The synthetic utility of 3-thioaryne intermediates has been demonstrated through an aryne relay approach. The efficient synthesis of o-silylaryl triflate-type 3-thioaryne precursors has been achieved by the regioselective silylthiolation of 3-(triflyloxy)arynes with silyl sulfides. Various 3-thioarynes were successfully generated from these precursors and reacted with various arynophiles to afford
the presence of gold nanoparticles supported on ZrO2 proceeded efficiently under mild reaction conditions to give the corresponding allyl sulfides in excellent yields. ZrO2-Supported gold nanoparticles showed excellent catalytic turnover and reusability. In addition, the C–O bonds of benzyl and propargyl phosphates underwent thioetherification to afford benzyl and propargyl sulfides. The reaction of
Sulfur–silicon bond activation catalysed by Cl/Br ions: waste-free synthesis of unsymmetrical thioethers by replacing fluoride catalysis and fluorinated substrates in SNAr reactions
In contrast to conventional activation of NuâSiR3 reagents by F ion attributed to the strong affinity of Si to F, SâSi activation can now be achieved using Cl/Br ions of TBAX as catalysts via formation of weaker XâSi bonds and Me3SiâX. This led to a waste-free synthesis of unsymmetrical thioethers via F-free SNAr reactions of activated (hetero)aryl halides and RSâSiMe3, with recovery of the useful Me3SiâX reagent in high yields.