title: Total synthesis of the Daphniphyllum alkaloid daphenylline.
abstract: The Daphniphyllum alkaloids are a large class of natural products isolated from a genus of evergreen plants widely used in Chinese herbal medicine. They display a remarkable range of biological activities, including anticancer, antioxidant, and vasorelaxation properties as well as elevation of nerve growth factor. Daphenylline is a structurally unique member among the predominately aliphatic Daphniphyllum alkaloids, and contains a tetrasubstituted arene moiety mounted on a sterically compact hexacyclic scaffold. Herein, we describe the first total synthesis of daphenylline. A gold-catalysed 6-exo-dig cyclization reaction and a subsequent intramolecular Michael addition reaction, inspired by Dixon's seminal work, were exploited to construct the bridged 6,6,5-tricyclic motif of the natural product at an early stage, and the aromatic moiety was forged through a photoinduced olefin isomerization/6π-electrocyclization cascade followed by an oxidative aromatization process.
authors.affiliation: State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
authors.forename: Zhaoyong
authors.initials: Z
authors.lastname: Lu
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Deng
authors.forename: Ang
authors.initials: A
authors.lastname: Li
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis*; D002384:Catalysis; D031995:Saxifragaceae / Q000737:chemistry*
chemical_list: D000470:Alkaloids; C541594:daphenylline