Total synthesis and bioactivities of two proposed structures of maresin.

Maresin is a potent anti-inflammatory lipid mediator derived from docosahexaenoic acid (DHA). A highly convergent total synthesis of two proposed structures of C7-epimeric maresins from the four known fragments was achieved in 17 steps. The three key coupling reactions were the BF(3)-mediated alkyne attack on the epoxide, chiral titanium complex-promoted enantioselective alkyne addition to the aldehyde, and a Julia-Kocienski olefination. The two synthesized diastereomers were found to be comparably active in blocking neutrophil infiltration in the acute peritonitis model.