New method of alkenylation of anilines by acetylene compounds in the superacid HSO3F

Vinyl cations, generated by protonation of the triple bond of α,β-alkynylcarbonyl compounds in the superacid HSO3F, react efficiently with arylammonium (anilinium) ions at low temperatures −75 and −30 °C in 30–75 min with the formation of Friedel–Crafts-type products of anilinium ring alkenylation in 14–62% yields. Regio- and stereoselectivity of such electrophilic aromatic substitution has been studied in detail.