Intramolecular azide-alkene cycloaddition-elimination reaction in an aldohex-2-enonic acid derivative

REPETTO, EVANGELINA; OLIVEIRA UDRY, GUILLERMO A.; VARELA, O.

CARBOHYDRATE RESEARCH

ELSEVIER SCI LTD

Año: 2019 vol. 483

0008-6215

A 6-azido-2-tosylenolate, obtained from D-glucono-1,5-lactone in six steps, underwent an intramolecular cycloaddition?elimination pathway under mild conditions, yielding a chiral, substituted 5,6-dihydro-4H-pyrrolo[1,2-c]-1,2,3-triazole. The conditions were optimized to give exclusive formation of the triazole. The mechanism appears to involve intramolecular ring closure via a 1,3-dipolar azide?alkene cycloaddition to give a 1,2,3-triazoline, followed by elimination of p-toluenesulfonic acid, leading to aromatization. Triazole products, obtained by chemical modification, are expected to display activity as enzyme inhibitors. Furthermore, partially protected derivatives of the 2-hexenoate were prepared as useful synthetic intermediates.