Catalytic oxidation of isosafrol by vanadium complexes

1,2-methylenedioxy-4(1-propenyl)benzene, isosafrol (1a), is an important intermediate for the synthesis of drugs like L-DOPA. In this work, different vanadium complexes have been evaluated as catalysts for the preparation of the corresponding double bond cleavage product, 3,4-methylenedioxybenzaldehyde, piperonal (2), and the corresponding epoxide, 2-methyl-3-[3′,4′-methylenedioxyphenyl]oxirane (3). When VCl2(salen) is used either with H2O2 60% or TBHP (5 M isooctane solution), the epoxide was the major product obtained in very good yields.