Functionalized 5-substituted thiazolidine-2-thiones were synthesized efficiently from alkyl allyl(alkyl/aryl)-dithiocarbamates via radical cyclization with the corresponding S-alkyl O-ethyl xanthates as the adscititious radical precursors. The application of the adscititious radical precursors improves not only the yields, but also the efficiency in the radical cyclization reaction significantly. The current adscititious radical precursor method provides a new strategy for the achievement and improvement of some radical reactions which are hardly or difficultly realized by the traditional direct methods.

The diastereoselectivity in the triethylamine-catalyzed sulfa-Michael addition of nitroalkenes and thiols was investigated. The sulfa-Michael addition is kinetic control at the beginning and thermodynamic control at the end for less bulky reactants. Thus, kinetic and thermodynamic-controlled adducts can be obtained as major products by controlling the reaction time in those cases. Linear nitroalkenes generally produce anti-adducts as major kinetic products due to favorable steric and stereoelectronic effects, but the diastereoselectivity decreases obviously with steric increase of the substituent located in the vicinal olefinic carbon to the nitro group, even leading to syn-adducts as major kinetic products. 1-Nitrocyclohexene gives rise stereospecifically to kinetic cis-adduct, which epimerizes into more stable trans-adduct as major product through the thermodynamic equilibrium. However, the Michael additions involving bulky reactants are generally slow, resulting in the direct generation of thermodynamic adducts.

Functionalized 5-substituted thiazolidine-2-thiones were synthesized efficiently from alkyl allyl(alkyl/aryl)-dithiocarbamates via radical cyclization with the corresponding S-alkyl O-ethyl xanthates as the adscititious radical precursors. The application of the adscititious radical precursors improves not only the yields, but also the efficiency in the radical cyclization reaction significantly. The current adscititious radical precursor method provides a new strategy for the achievement and improvement of some radical reactions which are hardly or difficultly realized by the traditional direct methods.