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Synthesis and Stereochemistry of Some Bicyclic γ-Lactones from Parasitic Wasps (Hymenoptera: Braconidae). Utility of Hydrolytic Kinetic Resolution of Epoxides and Palladium(II)-Catalyzed Hydroxycyclization−Carbonylation−Lactonization of Ene-diols

2001; American Chemical Society; Volume: 66; Issue: 22 Linguagem: Inglês

10.1021/jo0159237

1520-6904

Gregory C. Paddon-Jones, Christopher S. P. McErlean, Patricia Y. Hayes, Christopher J. Moore, Wilfried Α. König, William Kitching,

Synthetic Organic Chemistry Methods

A palladium(II)-catalyzed hydroxycyclization−carbonylation−lactonization sequence with appropriate pent-4-ene-1,3-diols provides efficient access to the bicyclic γ-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.