Total synthesis of amphidinolide X.
A concise total synthesis of the cytotoxic marine natural product amphidinolide X (1) is described. A key step of the highly convergent route to this structurally rather unusual macrodiolide derivative consists of a newly developed, highly syn selective formation of allenol 6 by an iron-catalyzed ring opening reaction of the enantioenriched propargyl epoxide 5 (derived from a Sharpless epoxidation) with a Grignard reagent. Allenol 6 was then cyclized with the aid of Ag(I) to give dihydrofuran 7 containing the (R)-configured quarternary sp3 chiral center at C19 of the target. The anti-configured chiral centers at C10 and C11 were formed by the palladium-catalyzed, Et2Zn-promoted addition of propargyl mesylate 12 to the functionalized aldehyde 11. The key fragment coupling at the C13-C14 bond was achieved by the "9-MeO-9-BBN" variant of the alkyl-Suzuki reaction. Finally, the 16-membered macrodiolide ring was formed by a Yamaguchi esterification/lactonization strategy.
Lepage
Olivier
O
Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany.
Kattnig
Egmont
E
Fürstner
Alois
A
D000818:Animals; D004141:Dinoflagellida / Q000737:chemistry; D018942:Macrolides / Q000138:chemical synthesis*; D013237:Stereoisomerism; D000097442:Amphidinolides
D018942:Macrolides; C480942:amphidinolide X; D000097442:Amphidinolides