Total Syntheses of Ainsliadimer B and Gochnatiolides A and B

Abstract

Oh my goch: The total syntheses of ainsliadimer B and gochnatiolides A and B from α-santonin have been accomplished in 25 steps with approximately 1 % overall yield. A Diels-Alder reaction of natural dehydrozaluzanin C with a monomeric guaianolide derivative allows stereoselective assembly of a dimeric gochnatiolide-type skeleton with the required stereochemistry and preinstalled functionalities for the synthesis of dimeric ainsliadimer B and gochnatiolides A and B (see scheme).