THE TREMULANES, A NEW GROUP OF SESQUITERPENES FROM THE ASPEN ROTTING FUNGUS PHELLINUS-TREMULAE

A series of new sesquiterpenes, the tremulanes, possessing a previously unreported substituted perhydroazulene carbon skeleton, has been isolated from liquid cultures of the aspen (Populus tremuloides) rotting fungus Phellinus tremulae. The structures were determined by NMR techniques (H-1-H-1 COSY, HMQC, and HMBC) and other physical methods including, in the case of tremulenolide A (6), X-ray crystallography. The chemical correlation of tremulenediol A (10) with tremulenolide A (6) is described as is the correlation of tremulenedial (8) with tremulenediol B (11). The absolute configuration of the compounds is assigned by application of the olefin octant rule to the allylic alcohol tremulenediol A (10). These new sesquiterpenes do not obey the biogenetic isoprene rule and it is suggested that they may not be derived from farnesyl pyrophosphate.