Pigments of fungi, part 16. Synthesis of methyl ( R)-(+)-tetrahydro-2-methyl-5-oxo-2-furanacetate and its ( S)-(−)-antipode, chiroptical references for determination of the absolute stereochemistry of fungal pre-anthraquinones.

Abstract

The ( R)- and ( S)-butanolides 7 and 9 are synthesized via asymmetric epoxidation from geraniol; the ( R)-butanolide 7 is also obtained from ( S)- citramalic acid. The butanolides 7 and 9 are valuable reference compounds for the determination of absolute stereochemistry in fungal and plant pre-anthraquinones.