title: Synthesis and stereochemistry of some bicyclic gamma-lactones from parasitic wasps (Hymenoptera: Braconidae). Utility of hydrolytic kinetic resolution of epoxides and palladium(II)-catalyzed hydroxycyclization-carbonylation-lactonization of ene-diols.
abstract: A palladium(II)-catalyzed hydroxycyclization-carbonylation-lactonization sequence with appropriate pent-4-ene-1,3-diols provides efficient access to the bicyclic gamma-lactones, 5-n-butyl- and 5-n-hexyltetrahydrofuro-[3,2-b]furan-2(3H)-ones (3) and (4), respectively, in both racemic and enantiomeric forms. Some of the substrate pent-4-ene-1,3-diols of high enantiomeric excess (ee) have been derived from racemic terminal epoxides by hydrolytic kinetic resolution (HKR) using cobalt (III)-salen complexes. (9Z,12R)-(+)-Ricinoleic acid also serves as a "chiral pool" source of other pent-4-ene-1,3-diols. These syntheses and enantioselective gas chromatography confirm the structures and absolute stereochemistry of the lactones in some species of parasitic wasps (Hymenoptera: Braconidae). The highly abundant 5-n-hexyltetrahydrofuro-[3,2-b]furan-2(3H)-one (4) in Diachasmimorpha kraussii and D. longicaudata is of high ee (>99%) with (3aR,5R,6aR) stereochemistry.
authors.affiliation: Department of Chemistry, The University of Queensland, Brisbane, Q. 4072, Australia.
authors.forename: G C
authors.initials: GC
authors.lastname: Paddon-Jones
authors.forename: C S
authors.initials: CS
authors.lastname: McErlean
authors.forename: P
authors.initials: P
authors.lastname: Hayes
authors.forename: C J
authors.initials: CJ
authors.lastname: Moore
authors.forename: W A
authors.initials: WA
authors.lastname: Konig
authors.forename: W
authors.initials: W
authors.lastname: Kitching
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000138:chemical synthesis; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis*; D004330:Drosophila; D007306:Insecticides / Q000138:chemical synthesis; D007783:Lactones / Q000138:chemical synthesis*; D010271:Parasites / Q000737:chemistry; D013237:Stereoisomerism; D014863:Wasps / Q000737:chemistry*
chemical_list: D001685:Biological Factors; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007306:Insecticides; D007783:Lactones