Total Synthesis and Complete Stereostructure of a Marine Macrolide Glycoside, (-)-Lyngbyaloside B.

We have described in detail the total synthesis of both the proposed and correct structures of (-)-lyngbyaloside B, which facilitated the elucidation of the complete stereostructure of this natural product. Our study began with the total synthesis of 13-demethyllyngbyaloside B, in which an esterification/ring-closing metathesis (RCM) strategy was successfully used for the efficient construction of the macrocycle. We also established reliable methods for the introduction of the conjugated diene side chain and the l-rhamnose residue onto the macrocyclic framework.

Total synthesis, stereochemical reassignment, and biological evaluation of (-)-lyngbyaloside B.

(-)-Lyngbyaloside B is a 14-membered macrolide glycoside isolated from the marine cyanobacterium Lyngbya sp. as a cytotoxic substance by Moore and co-workers. The first total synthesis of (-)-lyngbyaloside B and the reassignment of its stereostructure is described.

Total synthesis of 13-demethyllyngbyaloside B.

Total synthesis of 13-demethyllyngbyaloside B, an unnatural analogue of a marine macrolide glycoside lyngbyaloside B, has been achieved. The 14-membered macrocyclic backbone was constructed in a convergent manner via esterification and ring-closing metathesis. The bromodiene side chain was introduced by means of a Stille-type reaction and a subsequent bromodesilylation.