Titanium silicalite 1 (TS-1) catalyzed oxidative transformations of furan derivatives with hydrogen peroxide

The oxidation of furan derivatives with titanium silicalite 1 (TS-1) and hydrogen peroxide is described. Oxidation products are identified and possible reaction pathways are discussed. It is shown that the oxidation of these compounds occurs via epoxidation of one of the furan double bonds. The initially formed epoxides immediately undergo rearrangement, furans yielding unsaturated 1,4-dicarbonyl compounds and furfuryl alcohols yielding 6-hydroxy-2H-pyran-3(6H)-ones. The latter compounds originate from cyclization of intermediate enedione alcohols. The presented method is particularly useful for the oxidation of 2,5-dimethylfuran to 3-hexene-2,5-dione and the conversion of furfuryl alcohol to 6-hydroxy-2H-pyran-3 (6H)-one, a versatile synthon in organic synthesis.