Tetrahydropyran synthesis mediated by catalytic triflic acid and hexafluoroisopropanol

Abstract A Brønsted acid-catalyzed regioselective intramolecular hydroalkoxylation is described. This reaction proceeds via a carbocation intermediate and enables the preparation of 1,1,1’-trisubstituted tetrahydropyran derivatives under mild conditions using catalytic triflic acid (TfOH) and hexafluoroisopropanol (HFIP) as a mediator. Graphical abstract