Synthesis of (−)-pregaliellalactone, conversion of (−)-pregaliellalactone to (−)-galiellalactone by mycelia of Galiella rufa

An enantioselective synthesis of (−)-pregaliellalactone (), a biosynthetic precursor of the potent fungal metabolite (−)-galiellalactone () produced by several ascomycetes, is reported. When fed to a culture of Galiella rufa, was efficiently converted to .