Stereoselective synthesis of 2,3-disubstituted dihydrobenzofuran using alkyne Prins type cyclization to vinylogous carbonates

An intramolecular, alkyne Prins type cyclization of vinylogous carbonates derived from o-alkynyl phenols is developed for the stereoselective construction of trans-2,3-disubstituted dihydrobenzofuran derivatives. Strong Lewis acids like TMSOTf catalyse this reaction efficiently. The presence of mildly electron donating groups on aryl rings increases the efficiency of the reaction. © Indian Academy of Sciences.