Pigments of fungi. LII - Anisochiral flavomannin 6,6 ',8-tri-O-methyl ether from an Australian Dermocybe toadstool

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 t he (3S,3'S,P)- and (3R,3'R,M)-enantiomers (5) and (7), respectively, in whi ch the former predominates to the extent of 50% e.e. The structure of the n atural product is determined by spectroscopic methods and the absolute conf iguration 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.