Isolation of the 3′R and 3′S diastereomers of fasciculic acid C from the Australian mushroom Hypholoma australianum

Abstract Nine compounds including the new diastereomers (3′R)-fasciculic acid C (1) and (3′S)-fasciculic acid C (2), the triterpenes (3–5), the sesquiterpenes (6–7) and the diketopiperazines (8–9) were isolated from the Australian mushroom Hypholoma australianum. Several lanostane triterpenes have been isolated from the genus Hypholoma previously contain a 3-hydroxy-3-methylglutaric acid or a 3-hydroxy-3-methylglutaryl-glycine side chain. Only Hypholoma derived triterpenes possessing the S-configuration for these two side chains have been isolated previously. Compound 1 is the first example of a triterpene isolated from Hypholoma to have an R-configuration for the side chain.