Synthesis of ACE tricyclic systems of daphnicyclidin A and dehy-droxymacropodumine A

The synthesis of the ACE tricyclic system of daphnicyclidin A and dehydroxymacropodumine A are developed. The key reactions include an efficient aldol reaction to introduce chiral fragment 33 for further construction of piperidine ring B and seven membered ring C, a nucleophilic addition of lithium pentene to aldehyde for installation of ring E, and a photocatalytic decarboxylation conjugate addition to construct ring C. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.