A new and versatile synthetic route for 8‐oxoprotoberberine 17 through synthesis of isoquinolinone 16 and construction of a B‐ring is described. The key step is the synthesis of isoquinolinone 14 through thermal cyclization of 2‐alkynylbenzaldehyde oxime 12 to afford isoquinoline N‐oxide 13, followed by a Reissert–Henze‐type reaction. The first total synthesis of 8‐oxoprotoberberine alkaloid alangiumkaloids A and B was achieved by using this strategy.
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.