Syntheses with a Chiral Building Block from the Citric Acid Cycle: (2R,3S)-Isocitric Acid by Fermentation of Sunflower Oil

摘要

The citric acid cycle constitutes a main metabolic process. Since its discovery in 1937 by H. A. Krebs, all of its intermediates have. been prepared in multigramm amounts—with one exception: (2R,3S)-isocitric acid (1, D_S-threo-isocitric acid). As a new member of the chiral pool it would be an interesting starting material for organic synthesis. This chiral α-hydroxy tricarboxylic acid is mainly accompanied by its constitutional isomer, citric acid (2). However, attempts to separate 1 from 2 have so far been successful only on an analytical scale.