Synthesis of macrotetrolide α, a designed polynactin analog composed of bishomononactic acids

Macrotetrolide α (1), a designed polynactin analog composed of (+)- and (−)-bishomononactic acids, was synthesized. The monomeric acids were prepared using cis-selective iodoetherification and optical resolution of the corresponding O-acetylmandelates as the key steps. Esterification and macrolactonization of the monomers were performed by Corey-Mukaiyama-Gerlach method. Compound 1 showed no immunosuppressive activity contrary to other natural polynactin congeners.