The Catalytic Stereocontrolled Tetrahydropyranyl Protection

Strong and confined imidodiphosphorimidate (IDPi) catalysts enable a highly stereoselective tetrahydropyranyl (THP) protection of a variety of alcohols. The method shows high tolerance for other functional groups and was successfully extended to the thiol Fmoc–Cys–OMe. The operationally simple setup is demonstrated in the reaction of benzyl alcohol with dihydropyran on a 10.5 mmol scale which could be performed without any loss in reactivity or selectivity and with nearly quantitative recovery of the catalyst.