Application of the intramolecular Diels–Alder vinylarene (IMDAV) reaction for the synthesis of benzo- and carbocyclofuroisoindole carboxylic acids and its limitations

Abstract

Furylallylamines, readily accessible from the corresponding furylacroleins, react with maleic, citraconic and trifluoromethylmaleic anhydrides to form furo[2,3-f]isoindolic acids. The reaction involves two successive steps: the acylation of the nitrogen atom of the initial allylamine and the subsequent intramolecular Diels–Alder vinylarene (IMDAV) reaction. The scope and limitations of the proposed method were thoroughly investigated. The key step, the IMDAV reaction, proceeds through an exo-transition state, giving rise to the exclusive formation of a single diastereomer of the target heterocycle. The obtained furo[2,3-f]isoindole carboxylic acids can serve as polyfunctional substrates for further transformations.