An Efficient Synthesis of 5,7-Dihydroxy-4-methylisobenzofuran-1(3N)-one, a Metabolite of aspergillus flavus and a Key Intermediate in the Synthesis of Mycophenolic Acid

An efficient new synthesis of 5,7-dihydroxy-4-methylisobenzofuran-1(3H)-one, a metabolite of aspergillus flavus and a key intermediate in the synthesis of mycophenolic acid, is reported. The new synthesis involves the preparation of 1,2-dihydro-4,6-dimethoxy-3-methylbenzocyclobuten-1-ol and a regioselective β-scission of alkoxyl radical generated from it with lead tetraacetate as the key steps.