A divergent strategy for the total syntheses of the indole terpenoid anominine (1) and its natural congener tubingensin A (2) has been developed. The common intermediate 11 bearing all of the required stereogenic centers for both natural products was first assembled by employing a Ueno-Stork radical cyclization and a Sc(OTf)(3)-mediated Mukaiyama aldol reaction to form the key C-C bonds in a stereocontrolled manner. The route to anominine features a radical deoxygenation followed by an efficient side-chain installation, while the path to tubingensin A exploits a CuOTf-promoted 6π-electrocyclization/aromatization sequence to forge the central region of the pentacyclic scaffold.
The total synthesis of epoxyeujindole A, a structurally unusual indole diterpenoid isolated from Eupenicillium javanicum, has been accomplished for the first time. The synthesis features a late-stage cationic cyclization strategy, which took advantage of an electron-rich olefinic substrate. The CDE ring system was assembled via an enantioselective conjugate addition/alkylation, a Luche cyclization, and a Nozaki-Hiyama-Kishi reaction. The heavily substituted A ring was constructed through a Suzuki-Miyaura coupling and a cationic cyclization, and the bridged fused B ring was formed through a Prins reaction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.