Absolute Configuration of (+)-Aureothin: A Toxic Metabolite Possessing γ-Pyrone Unit

Abstract
The absolute configuration of aureothin (1) has been determined by synthesis of (−)-aureonone (4) bearing R-configuration. X-Ray single crystallographic analysis of 21 guaranteed the stereochemistry of the chiral center introduced by Sharpless asymmetric epoxidation, as well as that of isoaureothin (3) which was previously synthesized in a similar pathway. Aureothin (1) itself was also synthesized, although Wittig coupling reaction of 4 under basic conditions, caused a partial epimerization of the chiral center.