6251-33-8Relevant articles and documents
A kinetic investigation, supported by theoretical calculations, of steric and ring strain effects on the oxidation of sulfides and sulfoxides by dimethyldioxirane in acetone
Hanson, Peter,Hendrickx, Ramon A. A. J.,Lindsay Smith, John R.
, p. 65 - 84 (2011/01/07)
The oxidations of alkyl 4-nitrophenyl, and dialkyl, sulfides and sulfoxides by dimethyldioxirane in acetone occur by concerted mechanisms but the sulfides respond differently from the sulfoxides to variation in the alkyl group. The reactions of the sulfides are inhibited by the steric effects of alkyl groups and these predominate over their inductive effects. By contrast, the reactions of these limited sets of sulfoxides are insensitive to alkyl steric effects but there is an indication of steric acceleration when a broader set of sulfoxides is considered. This behaviour is rationalised in terms of the differences in dipolar charge and its solvation between the ground state and transition state for the two types of substrate. The oxidations of cyclic sulfides and sulfoxides also exhibit contrasting behaviour. The reactivity of the sulfides is insensitive to ring strain but is explicable in frontier orbital terms whereas that of the sulfoxides is partly dependent upon the change in ring strain between reactant and product on oxidation, a difference rationalised in terms of the relative positions of the transition states in the reaction coordinates of the two oxidations. The reactivity of 4-, 5- and 6-membered cyclic sulfoxides is also dependent on a ring-size related property of the transition state. Calculations at the B3-LYP/6-31G* level of density functional theory on both ground states and transition states, including simulation of solvation by acetone, strongly support the mechanistic conclusions reached in this and earlier work.
Sulphonate Esters as Sources of Sulphonyl Radicals; Ring-closure Reactions of Alk-4- and -5-enesulphonyl Radicals
Culshaw, Peter N.,Walton, John C.
, p. 1201 - 1208 (2007/10/02)
Alkyl alkanesulphonates and arenesulphonates were found to be useful sources of sulphonyl radicals, particularly for spectroscopic work, when treated with organotin or organosilyl radicals.Allyl, propynyl and penta-2,4-dienyl methanesulphonates gave, however, allyl, propynyl and pentadienyl radicals, respectively.Sulphonyl radicals generated in this way added efficiently to alk-1-enes with electron-releasing substituents, and the EPR spectra of the adduct radicals were recorded.A variety of radical initiation systems were tried on pent-4-enesulphonyl chloride.The pent-4-enesulphonyl radical cyclised mainly in the endo mode to give the six-membered-ring sulphone.Similarly, the hex-5-enesulphonyl radical cyclised to give thiepane 1,1-dioxide, with a seven-membered ring.The cyclohex-2-enylethanesulphonyl radical cyclised mainly in the exo mode to give 2-chloro-9-thiabicyclononane 9,9-dioxide.The mechanisms of these reactions are discussed.
PHOTOSENSITIZED OXYGENATION OF CYCLIC SULFIDES. SELECTIVE C-S BOND CLEAVAGE
Takata, Toshikazu,Ishibashi, Koichi,Ando, Wataru
, p. 4609 - 4612 (2007/10/02)
TPP-Senzitized photooxidation of five-membered ring sulfides in aprotic solvent afforded C-S bond cleavage products, unlike six- and seven-membered ring sulfides which gave only S-oxidation products.The products as well as substitution and concentration effects suggest that C-S bond cleavage depends upon acidity of α-proton of persulfoxide intermediate.
