Contribution to the total synthesis of caribenolide I

Stereoselective synthesis of C13–C29 fragment of caribenolide I, a potent antitumour macrolide isolated from a marine dinoflagellate Amphidinium sp. is described. The key step relies on a highly diastereoselective C-glycosylation, using a bulky chiral oxazolidin-2-thione, to control the absolute configuration of C21. The C24 and C25 stereogenic centres were controlled by the enantioselective vinylogous Mukayiama aldol reaction, whereas C14 and C16 stereogenic centres were built from a chiral bis-epoxide.