98289-55-5Relevant academic research and scientific papers
Vertical and nonvertical participation by sulfur, selenium, and tellurium
White, Jonathan M.,Lambert, Joseph B.,Spiniello, Marisa,Jones, Scott A.,Gable, Robert W.
, p. 2799 - 2811 (2007/10/03)
The mechanism of stabilization of positive charge on carbon by sulfur, selenium, or tellurium at the: β-position has been investigated kinetically, by measurement of rate enhancements, and structurally, by variation of the bond strength to the leaving group. Stabilization can occur either nonvertically with formation of a bridged intermediate or vertically through hyperconjugation within an open carbocation. We observed large rate enhancements (105 for S, 106 for Se) in 97% aqueous trifluoroethanol with trifluoroacetate as the leaving group. These enhancements are consistent with either mechanism. Product structures also are consistent with either mechanism. Nine crystal structures revealed that the bond to the leaving group (C-O) is lengthened by the presence of S or Se at the β-position, in proportion to the basicity of the leaving group. This lengthening is not accompanied by angle distortions expected for the bridging mechanism. The crystallographic data support vertical (hyperconjugative) character along the reaction coordinate, more so for selenium than sulfur.
Use of tert-Butyl Sulfoxides as Latent Sulfenyl Cation Equivalents
Brichard, M.H.,Musick M.,Janousek, Z.,Viehe, H.G.
, p. 2379 - 2386 (2007/10/02)
This paper reports a new and practical method of trifluoroacetoxysulfenylation of olefins, starting from t-butyl sulfoxides.The latter, in a mixture of trifluoroacetic anhydride and trifluoroacetic acid, do not undergo the Pummerer reaction.Instead, sulfenyltrifluoroacetates 2 are formed and they add in situ to olefins.
Additions to Alkenes via Metal Ion-Promoted Oxidation of Dialkyl and Diaryl Disulphides
Bewick, Alan,Mellor, John M.,Owton, W. Martin
, p. 1039 - 1044 (2007/10/02)
Reactions of alkenes with di-n-propyl, diphenyl, and dibenzyl disulphide in the presence of lead(IV) salts in trifluoroacetic acid-dichloromethane are described.The products, vicinal trifluoroacetoxysulphides, are obtained in higher yields with manganese(III) salts as the oxidant.Alternative reaction conditions with use of iron(III) salts or in the absence of added metal salts are also described.Trifluoroacetoxysulphides derived from diphenyl disulphide react with acetonitrile under Ritter conditions to give acetamidosulphides but trifluoroacetoxysulphides derived from dibenzyl disulphide only give the vicinal acetamidosulphides in poor yield as a result of an alternative reaction pathway affording benzylacetamide.Conversions of acetamidosulphides into aminosulphides and into acetamidothiols are described.
