title: Studies of a Diazo Cyclopropanation Strategy for the Total Synthesis of (-)-Lundurine A.
abstract: The bioactive Kopsia alkaloids lundurines A-D are the only natural products known to contain indolylcyclopropane. Achieving their syntheses can provide important insights into their biogenesis, as well as novel synthetic routes for complex natural products. Asymmetric total synthesis of (-)-lundurine A has previously been achieved through a Simmons-Smith cyclopropanation strategy. Here, the total synthesis of (-)-lundurine A was carried out using a metal-catalyzed diazo cyclopropanation strategy. In order to avoid a carbene CH insertion side reaction during cyclopropanation of α-diazo- carboxylates or cyanides, a one-pot, copper-catalyzed Bamford-Stevens diazotization/diazo decomposition/cyclopropanation cascade was developed, involving hydrazone. This approach simultaneously generates the C/D/E ring system and the two chiral quaternary centers at C2 and C7.
authors.affiliation: Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041 (P. R. China).
authors.forename: Hong-Xiu
authors.initials: HX
authors.lastname: Huang
authors.affiliation: Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041 (P. R. China).
authors.forename: Shuai-Jiang
authors.initials: SJ
authors.lastname: Jin
authors.affiliation: Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041 (P. R. China).
authors.forename: Jin
authors.initials: J
authors.lastname: Gong
authors.affiliation: Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041 (P. R. China). danzhang@scu.edu.cn.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041 (P. R. China).
authors.forename: Hao
authors.initials: H
authors.lastname: Song
authors.affiliation: Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041 (P. R. China). yongqin@scu.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Qin
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry*; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D011083:Polycyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D001391:Azo Compounds; D001688:Biological Products; D011083:Polycyclic Compounds; C000597197:lundurine A
keywords: Bamford-Stevens reaction; Kopsia alkaloid; diazo cyclopropanation; lundurine A; total synthesis