Sesquiterpenoids. Part XIV. The constitution and stereochemistry of culmorin

The mould metabolite culmorin has been degraded in a stepwise manner to tetrahydroeucarvone and converted in a simple reaction sequence to enantiolongiborneol. These and related studies have shown that culmorin is 2,6,6,9-tetramethyltricyclo[5,4,01,7,02,9]undecane-8,11-diol (Ia). The configurations assigned to the hydroxy-groups are based on chemical evidence and confirmed by appropriate n.m.r. studies.