Synthetic Studies on Halichondrin B, an Antitumor Polyether Macrolide Isolated from a Marine Sponge. 9. Synthesis of the C16-C36 Unit via Stereoselective Construction of the D and E Rings.

Abstract

The C16-C36 unit of halichondrin B was stereoselectively synthesized via the aldol condensation of two C16-C26 esters with the previously synthesized C27-C36 aldehyde followed by E ring construction. The C16-C26 esters were prepared starting from (2S)-3-hydroxy-2-methylpropionic acid and L-tartaric acid via construction of the D ring by iodoetherification.