Synthetic Study of Optically Active 3-Azabicyclo[3.3.0]octane-2,6,8-tricarboxylic Acid

Abstract

Synthesis of (1R,2S,5S,6R,8S)-3-azabicyclo[3.3.0]octane-2,6,8-tricarboxylic acid (2) from trans-4-hydroxy-L-proline (5) was attempted. A Diels–Alder reaction of 3,4-dehydroproline derivative 9 and cyclopentadiene afforded a single stereoisomer 11. The Diels–Alder adduct was smoothly converted to the hydrochloride of 2 (24) via RuO₄ oxidation. Although some racemization of the material or product was observed during the synthetic processes, the amino acid 24 proved to be optically pure.