title: Construction of tetracyclic 3-spirooxindole through cross-dehydrogenation of pyridinium: applications in facile synthesis of (±)-corynoxine and (±)-corynoxine B.
abstract: A facile and straightforward method was developed to construct the fused tetracyclic 3-spirooxindole skeleton, which exists widely in natural products. The formation of the tetracyclic 3-spirooxindole structure was achieved through a transition-metal-free intramolecular cross-dehydrogenative coupling of pyridinium, which were formed in situ by the condensation of 3-(2-bromoethyl)indolin-2-one derivatives with 3-substituted pyridines. As examples of the application of this new methodology, two potentially medicinal natural products, (±)-corynoxine and (±)-corynoxine B, were efficiently synthesized in five scalable steps.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201, Yunnan, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Shao
authors.forename: Dashan
authors.initials: D
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Deng
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Liu
authors.forename: Qin-Shi
authors.initials: QS
authors.lastname: Zhao
authors.forename: Chengfeng
authors.initials: C
authors.lastname: Xia
mesh_terms: D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D060326:Chemistry Techniques, Synthetic; D006859:Hydrogen / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry*; D000078183:Oxindoles; D011725:Pyridines / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D001688:Biological Products; D007211:Indoles; D000078183:Oxindoles; D011725:Pyridines; D013141:Spiro Compounds; C000600669:corynoxine; C000600670:corynoxine B; C022960:2-oxindole; D006859:Hydrogen