Pigments of Fungi. LII Anisochiral Flavomannin 6,6′,8-Tri-O-methyl Ether from an Australian Dermocybe Toadstool

Abstract

Flavomannin 6,6′,8-tri-O-methyl ether occurs in the fruiting bodies of the Australian toadstool Dermocybe sp. WAT 24274 as an anisochiral mixture of the (3S,3′S,P)- and (3R,3′R,M)-enantiomers (5) and (7), respectively, in which the former predominates to the extent of 50% e.e. The structure of the natural product is determined by spectroscopic methods and the absolute configuration and enantiomeric purity are deduced from the c.d. spectrum and by chemical degradation of the natural product to a mixture of stereoisomeric dihydroanthracenones that has been analysed by chiral h.p.l.c.