title: Enantioselective Total Synthesis of (+)-Steenkrotin A and Determination of Its Absolute Configuration.
abstract: The first enantioselective total synthesis of (+)-steenkrotin A has been achieved in 18 steps and 4.2 % overall yield. The key features of the strategy entail a Rh-catalyzed O-H bond insertion followed by an intramolecular carbonyl-ene reaction, two sequential SmI2 -mediated Ueno-Stork and ketyl-olefin cyclizations, and a cascade intramolecular aldol condensation/vinylogous retro-aldol/aldol process with inversion of the relative configuration at the C7 position. The absolute configuration of (+)-steenkrotin A was determined based on the stepwise construction of the stereocenters during the total synthesis.
authors.affiliation: Department of Chemistry, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China.
authors.forename: Saiyong
authors.initials: S
authors.lastname: Pan
authors.affiliation: Department of Chemistry, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China.
authors.forename: Beiling
authors.initials: B
authors.lastname: Gao
authors.affiliation: Department of Chemistry, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China.
authors.forename: Jialei
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Chemistry, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xuan
authors.affiliation: College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, 310036, P.R. China.
authors.forename: Hujun
authors.initials: H
authors.lastname: Xie
authors.affiliation: Department of Chemistry, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China. hfding@zju.edu.cn.
authors.forename: Hanfeng
authors.initials: H
authors.lastname: Ding
mesh_terms: D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001688:Biological Products; D004224:Diterpenes; C567997:steenkrotin A
keywords: carbenoids; fused-ring systems; natural products; radical reactions; total synthesis