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