30866-18-3Relevant academic research and scientific papers
Pyrolysis of (2-Phenylethyl)phenylsulfonium Ylides
Yoshimura, Toshiaki,Motoyama, Atsushi,Morishige, Akiko,Tsukurimichi, Eiichi,Shimasaki, Choichiro,Hasegawa, Kiyoshi
, p. 174 - 180 (2007/10/02)
In order to obtain information concerning the reaction mechanism of the pyrolysis of sulfonium ylides bearing a substituted phenyl group on the 2-position in the S-ethyl group of ethylphenylsulfonium ylide, (2-phenylethyl)phenylsulfonium bis(methoxycarbonyl)methylide (1) and dicyanomethylide(2) were subjected to pyrolysis in benzene.The reaction rates of 1 and 2 at 140 deg C were 6.0- and 3.2-times faster than those of ethylphenylsulfonium bis(methoxycarbonyl)methylide and dicyanomethylide, respectively.The activation parameters for 1 were ΔH++=125 kJ mol-1 and ΔS++=-3.8 JK-18mol-1, while those for 2 were ΔH++=124 kJ mol-1 and ΔS++=-2.5 JK-1 mol-1.Substituent efects on the β-phenyl groups in 1 and 2 afforded positive Hammett ρ-values: ρ = 0.49 (γ = 0.997) and ρ = 0.26 (γ = 0.993), respectively.From the obtained results, it was suggested that the pyrolysis proceeds through essentially a concerted intramolecular cis-elimination inclined toward a slightly carbanion-like type from an E1-like type by introducing a phenyl substituent at the 2-position of the ethyl group in the ethylphenylsulfonium ylide.
