2-Cyclohexen-1-thiol, preparation

The 1,3-cyclohexadiene could not be prepared with higher purity than 98% and hence the analysis based on the final products is less meaningful. The yield of 3- and 4-hydroxycyclohexenes show that only 31% (0.18 pmolJ /0.58 pmolJ ) of the OH radicals add to the double bonds. There is no information about the missing 44% (100% — 25%—31%). Von Sonntag and coworkers suggested that the yield of hydroxy cyclohexenes is not indicative of the OH addition to the double bonds due to non-quantitative reaction of the ally lie radical 1 (equation 10) with RSH. Since, in the case of 1,4-cyclohexadiene, they found complete material balance, they concluded that the alky lie radical formed in reaction reacts quantitatively with the thiolic compound. Thus, radical 2 formed in reaction (11) will react quantitatively with RSH. The inefficiency of the reduction of the allylic radical by the thiol is probably due to the weak ally lie C—H bond which leads to a six orders of magnitude lower rate constant for the RSH-I- allylic radical reaction compared with the RSH-I- alkyl radical reaction. If all the material imbalance is due to incomplete reduction of the allylic radical, its formation is the main path of reaction of OH with 1,3-cyclohexadiene. 

A simple example of substitution in a vinyl halide is the preparation of thiol derivatives of 1-cyclohexene from the thiol and sodamide in THF with chloro-1-cyclohexene (12) . ... 

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