Centro di Studio per la Chimica delle Sostanze Organiche Naturali del CNR, Dipartimento di Chimica, Universitd “La Sapienza”, P.le A. Moro 5, 00185 Rome, Italy. ... Abstract:1-Aryl-lr2-diketones 5 have been obtained by pyridinium chlorochromate oxidation of benzylketones 2. In the same way 2-buten-lI4-olide 2 and 3H-benzofuran-2-one 5 have been obtained. - ... The use of pyridinium chlorochromate as oxidizing reagent in a ... 5,6-dihydropyrans . We have attempted to ...