title: Enantioselective total synthesis of (-)-citrinadin A and revision of its stereochemical structure.
abstract: The first enantioselective total synthesis of (-)-citrinadin A has been accomplished in 20 steps from commercially available materials via an approach that minimizes refunctionalization and protection/deprotection operations. The cornerstone of this synthesis features an asymmetric vinylogous Mannich addition of a dienolate to a chiral pyridinium salt to set the initial chiral center. A sequence of substrate-controlled reactions, including a highly stereoselective epoxidation/ring-opening sequence and an oxidative rearrangement of an indole to furnish a spirooxindole, are then used to establish the remaining stereocenters in the pentacyclic core of (-)-citrinadin A. The successful synthesis of citrinadin A led to a revision of the stereochemical structure of the core substructure of the citrinadins.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas, Austin, Texas 78712, USA.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Bian
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Marvin
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Martin
mesh_terms: D060326:Chemistry Techniques, Synthetic; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D026121:Indole Alkaloids; C503673:citrinadin A