Thiyl type radical, free

This scheme appears to involve a free thiyl type radical (R2NCS.S). 

Only compounds of type I and II, which contain both metal and sulfur, were found to act as inhibitors. Compounds III and IV, for example, were ineffective. The inhibition of indene oxidation by zinc dithio-phosphates was considered to be a key result in this work since it rules out the intermediate formation of free thiyl radicals. There is adequate evidence (2, 9, 16, 17, 22) that thiyl radicals, including (RO)2PS2, add rapidly to olefins and that in the presence of oxygen the following sequence of reactions would occur. 

The kinetics of the decomposition of a number of hydroperoxides under the influence of organic sulfides has been studied [54]. In many works devoted to this problem, it is assumed that the interaction of the sulfide with hydroperoxides proceeds without the formation of free radicals. However, it was established in [52] by the method of electron paramagnetic resonance that in the presence of hydroperoxides, most sulfides or other sulfur-containing compounds capable of reacting with hydroperoxides react with stable diarylazotoxide radicals. The authors assume that the reaction of the sulfide with the peroxide leads to the formation of an active radical of the thiyl type, which recombines with the azotoxide radicals. 

It has long been known that unsymmetrical ketones can be prepared by the reaction of aldehydes with alkenes under free-radical reaction conditions. Recently the revision of this chemistry has been reported by the Roberts group [42], They introduced thiols as a polarity reversal catalyst for the addition of aldehydes to alkenes. Thiyl radicals are electrophilic, and therefore a polar Sh2 type transition state for the hydrogen transfer step from an aldehyde would be ideal in this situation. Indeed, the addition of aldehydes to a variety of alkenes can be effected by... 

The photoinduced addition of a thiol (RSH) to an olefinic double bond has been used to produce polymer networks by taking multi-functional monomers [37-44]. The thiol-ene polymerisation proceeds by a step growth addition mechanism which is propagated by a free radical, chain transfer reaction involving the thiyl radical (RS ). The initial thiyl radicals can be readily generated by UV-irradiation of a thiol in the presence of a radical-type photoinitiator. The overall reaction process can be schematically represented as follows ... 

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