The Total Synthesis of dl-Avenaciolide

The total synthesis of the mold product avenaciolide (1) is reported using the following sequence. Acylative decarboxylation of tricarballylic acid with nonanoic anhydride afforded the dilactone (26) of 3-(l,l-dihydroxy-nonyl)glutaric acid. Reduction of this dilactone by means of alkaline borohydride then led to (rows-tetrahydro-2-octyl-5-oxo-3-furanacetic acid (16) which was converted via its acid chloride to the pyrrolidine amide 32. Car-bomethoxylation of the latter compound afforded the amidolactonic ester 33. Treatment of this material with sodium hypochlorite solution followed by boiling both the neutral and acidic products with aqueous hydrobromic acid led to the dilactone 35. Carboxylation of 35 with methyl methoxymagnesium carbonate provided the di-lactonic acid 40 which when treated with formaldehyde and diethylamine in buffered acetic acid yielded cM-aven-aciolide(l).