The synthesis of natural R-(-)enantiomers from three galbanum resin macrolides

Article abstract of DOI:10.1055/s-1994-25676

The three macrolides 1, 2 and 3 isolated from galbanum resin were synthesized starting from ω-bromoacetals 9. The key step is the buffered intramolecular Wittig reaction of the ylides 14 and 23 to afford the α,β-unsaturated lactones 15, 16 and 24. Hydrogenation of these lactones gives the title macrolides in (R)-configuration.