Synthesis of the CtC18 fragment of Neaumycin B

摘要

Stereoselective synthesis of the Ct-Qs fragment 2 of Neaumycin B (1), 28-membered macrolide compound with 19-chiral centers and 6,6-spiroketal structure, has been described. Brown syn-crotylation and olefin metathesis reaction were used as key steps from (R)-roche ester in the synthesis of C8-Cq8 fragment 3. Q-Cy fragment 4 was constructed from 1,3-propanediol using diastereoselective allylation, syn-aldol reaction, and olefin metathesis reaction as key steps. Finally, NHK reaction and (S)-CBS reduction as key steps led to the of synthesis of C1-C18 fragment 2 of Neaumycin B (1).