Oxidative addition and isomerization reactions. The synthesis of cis- and trans-ArSF₄Cl and cis- and trans-PhTeF₄Cl

Abstract

The stereoselective synthesis and isomerization of cis- and trans-ArSF4Cl is described, where Ar = Ph, p-MeC6H4, and p--O2NC6H4. Also briefly described is the synthesis of ArSF5, cis- and trans-PhTeF4Cl, and PhTeF5. The oxidative halogenating reagent is a mixture of XeF2 and Cl−, and suitable starting compounds are ArSSAr, ArSF3, and PhTeTePh. Products were characterized by 19F, 13C, and 125Te NMR spectroscopy, and by the 37Cl/35Cl and 34S/32S isotope effects on the 19F NMR chemical shifts. A mechanism of oxidative halogenation is proposed to account for the stereoselective synthesis of cis- and trans-ArSF4Cl. Ab initio calculations of optimized geometries of anionic and radical intermediates, i.e., PhSF3X− and PhSF3X• (X = F, Cl), were carried out with the aid of the GAUSSIAN 92 program. Key words: synthesis of cis- and trans-ArSF4Cl, cis- and trans-PhTeF4Cl, ArSF5, and PhTeF5, mechanism of oxidative fluorination and oxidative chlorination, 37Cl/35Cl and 34S/32S isotope effects on 19F NMR spectra.

Discovery of practical production processes for arylsulfur pentafluorides and their higher homologues, bis- and tris(sulfur pentafluorides): Beginning of a new era of “super-trifluoromethyl” arene chemistry and its industry

“…It is noticeable that, except for the polyfluorinated compounds and others discussed above, trans -isomeric ArSF 4 Cl was exclusively formed by the reactions of Ar 2 S 2 with Cl 2 /KF, while the reactions of Ar 2 S 2 with XeF 2 /Et 4 NCl gave a mixture of cis- and trans -isomers according to Janzen's report [52]. Janzen proposed radical reactions with Cl · species [52].…”

“…Janzen proposed radical reactions with Cl · species [52]. The Cl 2 /KF reactions are ionic in nature, in which trans -form salts 8 exclusively form and react with Cl 2 to give the trans -isomers.…”

Ar-SF 4 Cl Deoxofluorination

“…Janzen reported the preparation of ArSF 4 Cl (Ar = Ph, p-MePh, p-NO 2 Ph) by the reaction of diaryl disulfides (ArSSAr) with XeF 2 in the presence of tetra-ethylammonium chloride [32]. Fifteen years later, Umemoto reported a practical method for the preparation of ArSF 4 Cl by the reaction of ArSSAr or aryl thiols (ArSH) with an excess amount of chlorine in the presence of potassium fluoride or cesium fluoride in dry acetonitrile between 0 C and room temperature [40,41] (Fig.…”

“…Chemical shifts of 19 F NMR of phenylsulfur chlorotetrafluoride (PhSF 4 Cl) are shown in Fig. 4 [32]. The cis-isomer of PhSF 4 Cl is less stable and is generally isomerized into the corresponding trans-isomer with some exceptions [24,32,40].…”

37,35Cl isotope effects on19F and13C chemical shifts of chlorofluoro- and hydrochlorofluorocarbons

“…17 Bernard and Schurko reported three-and four-bond 37 Cl/ 35 Cl and 81 Br/ 79 Br isotope shifts on the 19 F NMR spectra of some substituted benzenes, 18 and in 1996, Schaefer et al established the existence of five-bond chlorine isotope effects on the 19 F NMR spectrum of 1-chloro-2,4-difluorobenzene. 19 20 There are a number of earlier publications that report chlorine isotope effects on 13 C shifts. 21 -23 The broadenings in the 13 C resonances of CH 2 Cl 2 and CHCl 3 were observed by Everett.…”