Natural acetylenes. Part XVIII. Some allenic polyacetylenes from basidiomycetes

Abstract

The isolation, characterisation, and structure determination of ten polyacetylenes, including seven new allenic-diactylenes, from five Basidiomycete fungi (Cortinellus berkeleyanus, Odontia bicolor, Flammula sapinea, Daedalea juniperina, and the unidentified fungus B285) are described. The new allenic-diacetylenes are (a) HCC·CC·CHCCH·[CH₂]_n·OH (n= 1, 3, and 4); (b) HCC·CC·CHCCH·CH(OH)·[CH₂]_n·OH (n= 2 and 3); (c) HCC·CC·CHCCH·CH₂·CH(OH)·CH₂·CH₂·OH; and (d) CH₃·CC·CC·CHCCH·CH₂·CH₂·OH. The diols (b; n= 2) and (c) were conveniently purified and examined as their isopropylidene derivatives.

With the alcohols (a; n= 3 and 4), base-catalysed isomerisation, presumably intramolecularly assisted by the alkoxide anion, unexpectedly leads to disubstituted triacetylenic alcohols, CH₃·(CC)₃·[CH₂]_n·OH. The sign of the very large optical rotations of these metabolities probably indicates the absolute configuration of the allene grouping.