Syntheses of Unsaturated Lactones

Lactones 41. Synthesis and microbial hydroxylation of unsaturated terpenoid lactones with p-menthane ring systems.

Racemic [(±)-4-isopropyl-1-methyl-7-oxa-cis-bicyclo[4.3.0]non-4-en-8-one] and optically active δ,ε-unsaturated lactones [(-)-(1R,6R)-4-isopropyl-1-methyl-7-oxabicyclo[4.3.0]non-4-en-8-one and (+)-(1S,6S)-4-isopropyl-1-methyl-7-oxabicyclo[4.3.0] non-4-en-8-one)] with the p-menthane system were obtained and their odoriferous properties were evaluated. Biotransformations of the racemic lactone wit...

Enantioselective syntheses of 3,4,5-trisubstituted c-lactones: formal synthesis of ( )-blastmycinolactol

A kinetic resolution process of Rh-catalyzed intramolecular Alder-ene reaction is described along with the studies of the substrate scope and stereochemistry of this remarkably efficient process. 3,4,5-Trisubstituted c-lactones were synthesized in high enantioselectivity (>99% ee) and efficiency. The formal asymmetric syntheses of ( )-blastmycinolactol and (+)-blastmycinone, degradation product...

Divergent syntheses of resorcylic acid lactones: L-783277, LL-Z1640-2, and hypothemycin.

The resorcylic acid lactones (RAL) are endowed with diverse biological activity ranging from transcription factor modulators (zearalenone and zearalenol) to HSP90 inhibitors (radicicol and pochonin D) and reversible (aigialomycin D) as well as irreversible kinase inhibitors (hypothemycin and other RAL containing a cis-enone). Our interest in broadening the diversity of this family beyond natura...

Synthesis and Biotransformation of Bicyclic Unsaturated Lactones with Three or Four Methyl Groups.

The aim of this study was to obtain new unsaturated lactones by chemical synthesis and their microbial transformations using fungal strains. Some of these strains were able to transform unsaturated lactones into different hydroxy or epoxy derivatives. Strains of Syncephalastrum racemosum and Absidia cylindrospora gave products with a hydroxy group introduced into a tertiary carbon, while the Pe...

Palladium-catalyzed carbonylation of 2-(propargyl)allyl phosphates leading to highly unsaturated gamma-lactones.