Alkylthiylation of triquinphosphoranes by disulfides: an entry to chiral thiatriquinphosphoranes

Triquinphosphoranes 1 undergo alkylthiylation reactions, even in the dark, with methyl and n-butyl disulfides to give the corresponding thiaphosphoranes with high yields. Chiral triquinphosphorane 2, by this reaction, gives rise to chiral thiatriquinphosphorane 4. The reaction with t-BuSSBu-t preferably gave the thiophosphoramide. An increased reactivity was observed when the experiments were conducted under UV irradiation.