Heteropoly acid catalysts in Prins cyclization for the synthesis of Florol®

H3PW12O40 heteropoly acid supported on SiO2 and its bulk acidic cesium salt Cs2.5H0.5PW12O40 are demonstrated to be highly active and recyclable solid catalysts for Prins cyclization allowing for the clean, high-yielding synthesis of Florol® from isoprenol and isovaleraldehyde. Florol®, a valuable floral odorant employed in a vast variety of commercial products, was obtained in ca. 80 % yield under nearly ambient conditions. Dimethylcarbonate or diethylcarbonate used as green reaction media, low catalyst loadings and moderate conditions are important features that contribute for the sustainability of the method.