A Novel Synthesis of the Naturally Occurring Dibenzofurans Pannaric Acid and Schizopeltic Acid

Abstract

The dibenzofurans schizopeltic acid (1) and pannaric acid (2) have been synthesized by utilizing a biomimetic approach. The depside methyl 4-O-benzyllecanorate (6) has been converted into the diphenyl ether (7) in high yield by treatment with base. Appropriate modification of this diphenyl ether followed by cyclization with palladium acetate afforded the polysubstituted dibenzofurans (11) and (12) which were converted into the natural acids.