Alkynyl vinyl sulfides are prepared in good yield by reaction of lithium acetylides with the unsaturated sulfenamides 4 which in turn are easily synthesized by addition of phthalimidosulfenyl chloride to alkynes. In all cases the reaction occurs without effecting the stereochemistry of the double bond.
Vinylthio phthalimides 1, synthesized by addition of phtalimidosulphenyl chloride to some alkynes, react with 2 equivalents of lithiumtriethylboron hydride to give vinylthio substituted thiiranes 3 with high degree of diasteroselectivity. The reaction of 1 with 1 equivalent of the same hydride affords divinyl disulphides 6 which resulted to be intermediates in the formation of thiiranes 3 since the