53847-74-8Relevant articles and documents
Neighboring the effect in the oxidation of α-Stannyl phenyl vinyl sulfides
Glass, Richard S.,Guo, Qin,Liu, Yunqi
, p. 12273 - 12286 (2007/10/03)
α-Stannyl vinyl sulfides were generally prepared by hydrostannylation of thioacetylenes catalyzed by Pd(PPh3)4. The regio- and stereochemistry of the products was determined unequivocally in three cases by X-ray crystallographic stru
Reductive alkylation of electronegatively-substituted alkenes by alkylmercury halides
Russell, Glen A.,Shi, Bing Zhi,Jiang, Wan,Hu, Shuiesheng,Kim, Byeong H.,Baik, Woonphil
, p. 3952 - 3962 (2007/10/02)
Photolysis of alkylmercury halides in the presence of electronegatively-substituted 1-alkenes yields adduct radicals [RCH2CH(EWG).] that in some cases react with RHgX to form RCH2CH(HgX)(EWG), e.g., EWG = (EtO)2PO or PhSO2. When the EWG is carbonyl or cyano, the resonance stabilized adduct radicals fail to react with the alkyl mercury halide. In these cases photolysis with RHgCl/KI in Me2SO leads to the adduct mercurial via reaction of the adduct radicals with RHgI2-. The reactions of tertiary-enolyl adduct radicals are inefficient with RHgX/KI, and disproportionation of the adduct radicals is the major reaction pathway. For secondary- or tertiary-adduct radicals the reductive alkylation products are formed in excellent yield by reaction with RHgCl and silyl hydrides in Me2SO solution in a process postulated to involve RHgH as an intermediate. The relative reactivities of a number of α,β-unsaturated systems toward t-Bu. have been measured by competitive techniques. The results demonstrate a high reactivity of s-cis enones relative to the s-trans conformers.
Free-Radical Reactions of Benzenethiol and Diphenyl Disulphide with Alkynes. Chemical Reactivity of Intermediate 2-(Phenylthio)vinyl Radicals
Benati, Luisa,Montevecchi, Pier Carlo,Spagnolo, Piero
, p. 2103 - 2109 (2007/10/02)
Reaction of benzenethiol at 100 deg C with neat alkyl- and dialkyl-acetylenes leads to virtually quantitative formation of isomeric mixtures of (E)- and (Z)-vinyl sulphide adducts in ratios which depend largely upon both the extent and the nature of alkyl substitution.Results are explained in terms of rapidly interconverting sp2-hybridized (E)- and (Z)-1-alkyl-2-(phenylthio)vinyl radical intermediates which can undergo hydrogen transfer from benzenethiol to an extent which is essentially dependent upon the steric hindrance of their cis-2-substituent.Consistent results are provided by related radical reactions of diphenyl disulphide with alkyl-substituted alkynes to afford varying amounts of 1,2-bis(phenylthio)ethylene adducts ascribable to SH2 reaction of the resulting 1-alkyl-2-(phenylthio)vinyl radicals with the disulphide present.Under analogous conditions benzenethiol and diphenyl disulphide react with phenylacetylenes to give vinyl sulphide or bissulphide adducts in a trans-stereoselective fashio.The findings are interpreted by suggesting, for the intermediate sp-hybridized 1-phenyl-2-(phenylthio)vinyl radicals, the occurrence of significant bonding interaction between the unpaired electron and the adjacent sulphur, which would essentially prevent attack of radical scavenger on the side cis to PhS.Evidence is also presented that 1-phenyl-2-(phenylthio)vinyl radicals can exhibit homolytic intramolecular cyclization reactions, leading to benzothiophene products to a comparatively much greater extent than the 1-alkyl-2-substituted analogues; however, 1-tert-butyl-2-(phenylthio)vinyl radical would represent a special case.
