Intramolecular Diels-Alder Additions of Benzynes to Furans. Exploratory Studies

Abstract

A series of 3-alkoxyanthranilic acids, in which a furan ring is attached to the terminal carbon atom of the alkoxy group, has been prepared. When the chain linking the anthranilic acid and furan ring systems is three or four atoms long, decomposition of the derived diazonium chlorides generates the corresponding benzynes , which are efficiently trapped intramolecularly by the furan moiety. Diazotization of 2-amino-3-furfuryloxybenzoic acid, where the linking chain is two atoms long, results in fragmentation with the formation of 6-diazo-5- oxocyclohexa-1,3-diene-1-carboxylic acid.