Abstract:
The diterpene hydrocarbon rimuene has exercised over the
years, the interest of a number of laboratories engaged in natural
product research. As is usual with this class of compound its
occurrence is confined almost entirely to the native New Zealand
flora and although only two types of tree have been used as sources,
it has been identified, often only in small amounts, in at least ten
different species. Its co-occurrence with other diterpenes of
similar chemical and physical properties has often made it hard to
isolate and this, together with its geographic distribution has
probably tended to limit its availability for research purposes,
and hence delayed the elucidation of its structure.
The awareness of the existence of this compound of undetermined
structure has, therefore, caused a noticable gap in the knowledge
of the diterpenoids, and this hiatus has been accentuated by
Wenkert who, believing it to have a pimarane skeleton, suggested
that it might be the important biogenetic precursor of a number of
tetracyclic diterpenoids. Recent work, confirmed by the present
investigation has, however, shown that previous structural predictions
were incorrect and in actual fact rimuene has a rosane
skeleton. As Ruzicka has shown for this class of compound,
it has probably been formed from a pimarane diterpenoid and therefore
represents a later biogenetic step than the other diterpene
hydrocarbons which are always found with it in nature.