Total Syntheses of Proposed Structures of 4,10-Dihydroxy-8,12-guaianolides

Abstract

The first total syntheses of two 4,10-dihydroxy-8,12-guaianolides that were reported to be natural products were achieved. Toward the syntheses of a collection of related guaianolides, the typical 5,7-fused system of 8,12-guaianolides was constructed by a ring expansion reaction of a hydroxylated coronafacic acid analogue that can be practically synthesized and optically resolved. The total syntheses of these compounds revealed that the previously reported structures of both natural products were incorrect.

Recent advances in the syntheses of guaianolides

“…8,12-Guaianolides are a less represented class though a few new molecules have been isolated recently. 57 (+)-Mikanokryptin 126 (Fig. 4) belonging to this class has been synthesized recently by Maimone and co-workers 58 in 2017 based on intermolecular and intramolecular double Barbier-type allylation for central 7-membered ring formation (Scheme 16).…”