Bis-esters from maleic anhydrides under neutral conditions: Protection of the anhydride of the natural product cornexistin

Article abstract of DOI:10.1016/0040-4039(96)00182-7

Trimethylsilyldiazomethane converts maleic anhydride derivatives in alcoholic THF to bis-esters. The highly acid and base sensitive natural product cornexistin was converted to its bis-methyl ester in 70-75% yield and to the mixed benzyl/methyl ester in 61% yield. The mixed ester can be converted back to cornexistin via transfer hydrogenation.