New route to o-terphenyls: application to the synthesis of 6,7,10,11-tetramethoxy-2-(methoxycabonyl)triphenylene.

The hydroxy-o-terphenylcarboxylic acid esters 6a-f have been prepared by benzannulation of the 5,6-diaryl-3-methoxycarbonylhexa-3,5-dienoic acids 5a-f using triethylamine-ethyl chloroformate, The application of this new synthesis of triphenylenes is illustrated through the synthesis of 2-methoxycarbonyl-6,7,10,11-tetramethoxytriphenylene 9.