title: Asymmetric Total Syntheses of Kopsia Indole Alkaloids.
abstract: The asymmetric total syntheses of a group of structurally complex Kopsia alkaloids, (-)-kopsine, (-)-isokopsine, (+)-methyl chanofruticosinate, (-)-fruticosine, and (-)-kopsanone, has been achieved. The key strategies for the construction of the molecular complexity in the targets included an asymmetric Tsuji-Trost rearrangement to set the first quaternary carbon center at C20, an intramolecular cyclopropanation by diazo decomposition to install the second and third quaternary carbon centers at C2 and C7, respectively, and a SmI2-promoted acyloin condensation to assemble the isokopsine core. A radical decarboxylation of an isokopsine-type intermediate results in a thermodynamic partial rearrangement to give N-decarbomethoxyisokopsine and N-decarbomethoxykopsine, two key intermediates for the syntheses of Kopsia alkaloids with different subtype core structures.
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: Lingying
authors.initials: L
authors.lastname: Leng
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: Xiaohan
authors.initials: X
authors.lastname: Zhou
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: Qi
authors.initials: Q
authors.lastname: Liao
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: Falu
authors.initials: F
authors.lastname: Wang
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.
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: Xiao-Yu
authors.initials: XY
authors.lastname: Liu
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: Yong
authors.initials: Y
authors.lastname: Qin
keywords: alkaloids; diazo compounds; natural products; rearrangements; total synthesis