Rhenium-Catalyzed Regio- and Stereoselective Synthesis of γ‑Thio-α,β-unsaturated Ketones via Insertion of Terminal Alkynes into the C–S Bond

The reaction of α-thioketones and alkynes in the presence of a rhenium catalyst, [HRe(CO)4]n, gave γ-thio-α,β-unsaturated ketones in excellent yields. The alkynes were inserted into the carbon–sulfur bond of the α-thioketones, and isomerization of a double bond provided the products with high regio- and stereoselectivities. This reaction also proceeded in an intramolecular fashion.