Total Synthesis of Clostrienose.

This paper considers the total synthesis of a cellular differentiation regulator of Clostridium acetobutylicum , clostrienose, which is a unique fatty-acid glycosyl ester consisting of clostrienoic acid, (3 R ,5 E ,8 E ,10 E )-3-hydroxy-tetradeca-5,8,10-trienoic acid and α-d-galactofuranosyl-(1 → 2)-α-l-rhamnose. The key features of our synthesis include stereoselective construction of a skipped-triene system in clostrienoic acid and its esterification with a disaccharide residue. The partially protected clostrienoic acid employed for the coupling also served for the preparation of l-rhamnosyl clostrienoate, thus leading to confirmation of the proposed structure unambiguously.