Transition Metal‐Free Stereoselective α‐Vinylation of Cyclic Ketones with Arylacetylenes in the Superbasic Catalytic Triad Potassium Hydroxide/tert‐Butyl Alcohol/Dimethyl Sulfoxide

A stereoselective α‐vinylation of cycloaliphatic ketones with arylacetylenes under the transition metal‐free conditions has been developed. The reaction is promoted by the superbasic catalytic triad potassium hydroxide/tert‐butyl alcohol/dimethyl sulfoxide (80–110 °C, 1–2 h) to afford mainly (E)‐β,γ‐ethylenic ketones, their (E)‐α,β‐isomers being minor products, in up to 83% total yield.