cycloisomerisation reaction of 1,6-enyne acetic esters have been developed. This cyclization reaction shows excellent regioselectivity and good functional group tolerance to obtain five-membered nitrogenated heterocyclic conjugatedtrienes in moderate to excellent yields. The resulting conjugatedtrienes could be facilely converted to highly substituted benzenes through Diels-Alder reactions.
heterocyclic compounds from hydroxylated enynes has been developed. In this reaction, hydroxylated enynes were selectively transformed into five‐membered heterocyclic compounds 2, with an allene moiety at the 3‐position, in the presence of F3CSO3H (0.1 mol %). When R1, R2=Ph, diphenylvinyl‐2,3‐dihydro‐1H‐pyrrole (2 y) was obtained. With HSbF6 (5 mol %) as the catalyst, polycyclic skeletons 3 and 4 with adjacent