A Highly Efficient and Chemoselective Synthetic Protocol for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols

Abstract

Abstract Various alcohols and phenols can be converted efficiently to the corresponding tetrahydropyranyl (THP) ethers in good yields using catalytic amounts of bromodimethylsulfonium bromide (0.005−0.02 equivalent) at room temperature. On the other hand, various THP ethers can also be deprotected to the parent alcoholic or phenolic compounds in CH 2 Cl 2 /MeOH (5:2) by employing 0.05 equivalent of the same catalyst. Some of the major advantages of this procedure are its mild conditions, that it is highly selective and efficient, high yielding, and cost‐effective, that it needs no solvent and is compatible with the presence of other protecting groups. Furthermore, no brominations occur at a double or triple bond, at an allylic position or even at an aromatic ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)