Polystyrene-supported GaCl3: A new, highly efficient and recyclable heterogeneous Lewis acid catalyst for tetrahydropyranylation of alcohols and phenols

A new, simple and highly chemoselective method for tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) in the presence of polystyrene-supported gallium trichloride (PS/GaCl3) as a highly active and reusable heterogeneous Lewis acid catalyst at room temperature is presented. In this catalytic system, primary, secondary and tertiary alcohols, as well as phenols, were converted to the corresponding tetrahydropyranyl (THP) ethers with short reaction times and high yields. The heterogenized catalyst is of high reusability and stability in the pyranylation reactions and was recovered several times with negligible loss in its activity and with negligible catalyst leaching, and also there is no need for regeneration. The method also shows good chemoselectivity for mono-tetrahydropyranylation of symmetrical diols.

A new, simple and highly chemoselective method for tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) in the presence of polystyrene-supported gallium trichloride (PS/GaCl3) as a highly active and reusable heterogeneous Lewis acid catalyst at room temperature is presented.Figure optionsDownload as PowerPoint slide