title: Total synthesis of (±)-carquinostatin a, and asymmetric total synthesis of (R)-(-)-carquinostatin a and (s)-(+)-carquinostatin a.
abstract: Total syntheses of (±)-carquinostatin A (1), and (R)-(-)-carquinostatin A (1a) together with its enantiomer, (S)-(+)-carquinostatin A (1b), possessing radical scavenging activity, were newly achieved. (±)-Carquinostatin A (1) was synthesized from 1-acetonyl-6-bromo-3-ethoxy-2-methylcarbazole (6), which was derived from the known 1-acetonyl-3-ethoxy-2-methylcarbazole (5). Introduction of a prenyl group at the 6-position of carbazole was successful in two steps. For the synthesis of (R)-(-)-carquinostatin A (1a) and (S)-(+)-carquinostatin A (1b), (R)-(-)-1-(2-acetoxypropyl)-3-hydroxy-2-methylcarbazole (15a) and (S)-(+)-3-hydroxy-1-(2-hydroxypropyl)-2-methylcarbazole (15b), prepared by lipase-QLM catalyzed enantioselective transesterification of 3-hydroxy-1-(2-hydroxypropyl)-2-methylcarbazole (14), were used as the chiral starting material.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729–0292, Japan.
authors.forename: Yuhzo
authors.initials: Y
authors.lastname: Hieda
authors.forename: Tominari
authors.initials: T
authors.lastname: Choshi
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Uchida
authors.forename: Haruto
authors.initials: H
authors.lastname: Fujioka
authors.forename: Sayuri
authors.initials: S
authors.lastname: Fujii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hibino
mesh_terms: D002227:Carbazoles / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D002227:Carbazoles; C113606:carquinostatin A