Synthesis of alkynyl sulfides resulting from a novel ring cleavage of 5-chloro-1,2,3-thiadiazoles in the presence of organometallic reagents

5-Chloro-1,2,3-thiadiazoles 2a,b were treated with organolithium and Grigna rd reagents giving a novel ring cleavage with the loss of nitrogen and chlo ride anion, resulting in the formation of alkynyl sulfides 9-14. The result s indicate that the mechanism of the reaction involves a concerted trans el imination of the leaving group.