Homochiral synthesis of paraconic acid and the biosynthesis of amphotericin B.

Homochiral (S)-(-)-paraconic acid was synthesised in 18% overall yield from (45)-4-isopropyl-2-oxazolidinone using titanium enolate methodology. Paraconic acid was used to synthesise A-factor. A-factor and analogues were fed to a culture of Streptomyces nodosus however no definitive enhancement, or a decrease in the lag time for the onset of metabolite production was observed. Sodium acetate-d3, [1-13C] and [3-13C]-propionate were fed to a culture of Streptomyces nodosus and label incorporation into amphotericin B of 10-15% was observed.