Syntheses of vinylindoles via a Brّnsted acid catalyzed highly regio- and stereoselective cis-hydroarylation of ynamides

A highly regio- and stereoselective Brønsted acid-catalyzed coupling of ynamides and indoles is described. This process is the equivalent of hydroarylation of ynamides and leads to the efficient syntheses of vinylindoles. Diels–Alder reaction between the vinylindoles and DMAD afforded carbazole derivatives in good yields.