Ionically Convoluted Polymeric Phosphotungstate

Significance

The solid-supported phosphotungstate catalyst was prepared via ionic convolution of H₃PW₁₂O₄₀ and linear poly(alkylpyridinium). Thus, the polymeric tungsten catalyst was readily prepared as a white insoluble powder by mixing poly[1,8-dibromooctane-co-1,3-di(4-pyridyl)propane] and H₃PW₁₂O₄₀ in water at 25 °C. The oxidative cyclization of alkenols and alkenoic acids (see scheme) with aqueous hydrogen peroxide producing furanyl and pyranyl carbinols was found to proceed smoothly in water in the presence of PW₁₂O₄₀ ^³- (14 examples, including 5 times reusing experiments).