Affiliation:
1. Laboratorium für Organische Chemie ETH Zürich Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
Abstract
AbstractThe first total synthesis of heavily oxidized cassane‐type diterpenoid neocaesalpin A (1) is disclosed. At the heart of the synthesis lies an intermolecular Diels–Alder reaction that rapidly assembles the target framework from commercial materials. A carefully orchestrated sequence of oxidations secured the desired oxygenation pattern. Late‐stage release of the characteristic butenolide occurred through a novel mercury(II)‐mediated furan oxidation. Successful extension of the route allowed preparation of neocaesalpin AA (2) as well as nominal neocaesalpin K (3) and suggested structural revision of neocaesalpin K, leading to the hypothesis that the two are likely the same natural product with correct assignment as 2.
Funder
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung