Author's Organization：Rikagaku Kenkyusho, The Institute of Physical and Chemical Research Rikagaku Kenkyusho, The Institute of Physical and Chemical Research Rikagaku Kenkyusho, The Institute of Physical and Chemical Research
c-Homofluorene (VI) having undeniable trans-A/B-ring fusion has been previously synthesized from 1-abietic acid (I). In order to have a standard trans-A/B-ring hydrofluorene (XIII), basic skeleton of gibberellin, c-homofluorene (VI) was chosen as starting material and its seven membered alicyclic C-ring was contracted to benzene ring.
