Heating to phenylacetylene with a mixture of thiophenol and dialkyl diselen
ide to 150-180 degreesC yields previously unknown products of simultaneous
addition to the phenylacetylene triple bond of alkyl-selenyl and phenthiyl
groups, 2-alkylselenyl-1-phenyl-1-phenylthioethenes. The free-radical react
ion mechanism is discussed.