Total synthesis of 3,3′,4-tri-O-methylellagic acid from gallic acid

Total synthesis of 3,3′,4-tri-O-methylellagic acid has been described from commercially available gallic acid. Construction of the crucial unsymmetric Ar-Ar bond has been carried out in various methods such as Heck coupling, Heck coupling followed by oxidation or anionic Fries rearrangement, Suzuki cross-coupling, etc., but all the attempts were unsuccessful. Then, finally it has been achieved by intramolecular Ullmann coupling reaction.

Graphical abstractTotal synthesis of 3,3,′4-tri-O-methylellagic acid has been achieved from gallic acid. Construction of crucial unsymmetric Ar-Ar bond was tried in various ways such as Ullmann cross-coupling, Suzuki cross-coupling, intramolecular Heck coupling, etc. But all the attempts were unsuccessful and finally it has been achieved by the intramolecular Ullmann coupling.Download full-size image