24 フェルネン類の合成研究

抄録

As the Synthetic approach to fernenes, a few attempts were made on the synthesis of trans-dimethylhydrophenanthrene (1), which corresponded to the B-C-D ring system of fernene. Acid-catalyzed cyclization of the phenethylcyclohexenone (3) proceeded stereoselectively to give the tricyclic compound (4). A cis-relationship of the two angular methyls of (4) was confirmed by an individual synthesis of authentic (11). The desired trans-compound (1) was obtained through a Claisen rearrangement of the vinyl ether (22), followed by several steps including a cyclization of (23). In this process, the required cyclohexenol (21a) was prepared effectively from the cyclohexenone (20) in three steps ; (20)-(21b)-(21a-benzoate)-(21a). These results were applied in the synthesis of (33). Moreover, the potent intermediate (41) was obtained through an amide-Claisen rearrangement of (35) which was converted to the lactone (37). The construction of the E ring system of fernenes using the diketone moiety of (41) is in progress.