A highly efficient synthetic protocol for tetrahydropyranylation/ depyranylation of alcohols and phenols

Article abstract of DOI:10.1002/ejoc.200500400

Bismuth(III) nitrate pentahydrate [Bi(NO₃)₃· 5H₂O] is found to be an effective catalyst for both tetrahydropyranylation and depyranylation of alcohols and phenols. Some of the major advantages of this protocol are: non-aqueous workup, good yields, the involvement of a less-expensive and nontoxic catalyst, and compatibility in the presence of a large number of other protecting groups. Notably, isopropylidene, benzylidene, and thioacetal groups are also unaffected under the experimental conditions. Remarkably, a selective mono-protection of diols and primary alcohols can be achieved chemoselectively by employing the same catalyst. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.