The structure of laricinolic acid and its biomimetic transformation into officinalic acid

Laricinolic acid (8), a new sesquiterpene of the drimane type, has been iso lated from the wood-rotting fungus Laricifomes officinalis. Its structure w as elucidated by spectroscopic means and confirmed via a correlation with t he known drimenine derivative 13. Oxidation of 8 to 1, followed by a mild t hermal treatment, furnished (-)-officinalic acid (4) in 65% yield. This tra nsformation establishes the hitherto unknown absolute configuration of the latter. An independent correlation was achieved by pyrolysis of 4 which fur nished (-)-dihydrooxoisodrimenine (14) of known absolute configuration.