Reductive addition of the benzenethiyl radical to alkynes by amine-mediated single electron transfer reaction to diphenyl disulfide.

Hydrothiolation of alkynes proceeds with diphenyl disulfide and tripropylamine. Amine-mediated single electron transfer to diphenyl disulfide can be proposed for the reaction mechanism. Applications of the method to radical cyclizations of eneyne compounds are also presented.