Constituents of the higher fungi. Part XII. Identification of involutin as (–)-cis-5-(3,4-dihydroxyphenyl)-3,4-dihydroxy-2-(4-hydroxyphenyl)-cyclopent-2-enone and synthesis of (±)-cis-involutin trimethyl ether from isoxerocomic acid derivatives

Abstract

Xerocomic and isoxerocomic acids have been synthesised and converted into the corresponding 2,5-diaryl-4-methoxycyclopent-4-ene-1,3-diones. Reduction of the dione from isoxerocomic acid has given racemic involutin trimethyl ether (IV); this identifies involutin as (III). Isoxerocomic acid is readily oxidised to xerocomorubin; this is compared with the naturally occurring variegatorubin.