Sulphonyl radicals

Absorption spectroscopy of sulphonyl radicals 1093, 1094 of sulphoxides 895, 897, 902-905 Acetoxysulphones 953 electrochemical reactions of 1036, 1037 / -Acyloxysulphones, desulphonylation of 948 Alcohols... 

Sulphonyl phosphates, reactions of 638 Sulphonyl radicals 215 cyclization of 1099 ESR spectra of 1090-1093 formation of 1094-1098 structure of 1090-1094 thermodynamic data for 1094 Sulphonyl sulphenes 196 Sulphonyl sulphoxides alkylation of 311 synthesis of 262... 

There is a parallel for oxygen abstraction by a sulphonyl radical either from nitrobenzene or by disproportionation thermolysis of benzenesulphonyldiazomethane (54) in benzene gives, among other products, some sulphonate ester (55) 67>, which has been formulated as follows ... 

R. Nouguier, C. Lesueur, E. De Riggi, M. P. Bertrand, and A. Virgili, Stereoselective free-radical cyclisation on a sugar template. Hie sulphonyl radical as a synthetic tool for functionalized glycosides. Tetrahedron Lett. 37 3541 (1990). 

The trends in the values of the EAs for both the XS03 - and XS02 series as a function of the substituent X are as expected, with the more electronegative group preferentially stabilizing the anion relative to the radical. The electron affinities of the sulphonyl radicals have not been treated before and these are the first published values. The EAs, of course, also give the first adiabatic ionization energies of the anions. 

A different type of a-sulphonyl radical is obtained when arenesulphonic acids or their sulphonyl fluorides are reacted with Pb02 in HS03F at ca 200 K. Under these conditions, electron transfer takes place to generate the radical cations of the parent compound (equation 17)40. 

TABLE 8. ESR spectral parameters for a-sulphonyl radicals of sulphones and sulphonic acids... 

The NMR and ESR spectra of sulphonic acids TABLE 9. ESR spectral data for a-sulphonyl radical cations40,41... 

There are many examples of the photochemical behaviour of these classes of compounds. The photochemistry is dominated by the fission of a C—S bond affording a carbon radical and a sulphonyl radical. The UY absorptions of these compounds are dependent upon the type of substituent attached to the sulphonyl group. Thus a dialkyl sulphone (19) shows an... 

Cleavage of the radical anion gives the sulphonyl radical (equation 33), which may react as shown in equations 34 and 35 ... 

Analogous relationships can be expected with phenolic sulphides. The unstable products of transformation are sources of thiyl, sulphinyl, and sulphonyl radicals, which may participate in the formation of sulphonate CXCV and other compounds present in the reaction mixture in very small amounts. It is possible that they are also the cause of formation of species which decompose catalytically tert-BuOOH (cf. also259)). 

In a further study of the Ce oxidizing system by e.p.r. methods, the rate of production of thiyl radicals was found to be ca. 10 1 mol s. Significant reactions in their subsequent oxidation were suggested to involve production of sulphinyl and sulphonyl radicals,... 

Thermolysis of phenylazo jp-tolyl sulphone in the presence of toluene-p-sulphonyl iodide is a convenient method for generating sulphonyl radicals (PhN=N-S02CeH4Me-p + p-MeC6H4S02l - Phi + p-MeC H4S02 ). 

Unimolecular rearrangement of thiylperoxyl radicals to sulphonyl radicals (both oxygen bonded to sulphur) has been described [94—96] ... 

A further complication, not kinetically characterized to the author s knowledge, is that oxygen could add to the sulphonyl radical to give a sulphonylperoxyl radical [96] ... 

The polymeric sulphonyl radicals (PSO2) formed by C—S bond cleavage can react with oxygen to give polymeric sulphonyl peroxy radicals (PSO2OO ) ... 

Continuing interest in rotation barriers about single bonds in acyclic radicals, as determined by the interpretation of e.s.r. data, is illustrated in a study of R CHSR radicals and alkane-, arene-, and alkoxy-sulphonyl radicals (obtained by high-intensity u.v. irradiation of sulphinic acids in the presence of di-t-butyl peroxide at low temperatures). Further evidence for hindered rotation about the C—S bond in these species is obtained, - and an unusual order of proton hyperfine splittings a 0-H)> a (a-H) a (y-H) is reported for propanesulphonyl radicals. The potential of the e.s.r. method in conformational analysis is shown in studies of radical cations (3) from 2,5-bis(alkylthio)thiophens, where the S-cis-cis conformer (3) is identified as more stable than other rotamers this is assumed to be the case too for the neutral molecule. 

Cleavage and Rearrangemoit of Sulidumes.—Sulphonyl radicals formed by cleavage of sulphones and sulphonamides in toluene soluticm over Na have been studied. Methyl heptafluoro-n-propyl sulphone rather remarkably undergoes hydrolysis in dilute aqueous NaOH at 100 °C to give MeSOjH and CFjCFiCHF. ... 

---