本論文報導具有順式十氫柰骨架的天然物- dihydroisochamaecynone (25) 的合成研究。整個合成策略的關鍵步驟是利用多重烯環化反應來建構出順式十氫柰骨架。
如 Scheme 13 β-酮酯化和物 (20) 可以從烯酮化合物 (52) 來合成。首先用甲基碘以及 4-溴-1-丁烯對化合物 (52) 進行烷化反應，得到化合物 (54)，接著用氫鋁化鋰 (LiAlH4) 還原後，加酸水解，使重排得到化合物 (55) 。之後進行甲氧羰基反應 (carbomethoxylation) 反應可得化合物 (56)，接之用 DDQ 進行氧化反應可得親二烯基 (16)。

親二烯基 (16) 用碘化鋅催化進行多重烯環化反應得化合物 (20)，然後將化合物 (20) 和甲基碘進行 O-alkylation 得化合物 (59) 。接著用氫鋁化鋰還原後，加酸進行脫水，即可得到化合物 (73)。之後再使用Wilkinsons,s catalyst 進行氫化反應可得到在結構上和天然物dihydroisochamaecynone (25) 更為接近的化合物 (76)，而這些研究將詳列於本論文中。

This thesis describes our efforts towards the total synthesis of dihydroisochamaecynone (25), a natural product containing a cis-decalin carbon skeleton core, using a polyene cyclization strategy recently developed in our laboratories. Towards this end, bicyclic enone (76),a projected advanced synthetic intermediate, has been synthesized staring with the readily available ethoxy enone (52).
Stork-Danheiser alkylations of enone (52), first with methyl iodide and then with 4-bromo-1-butene, gave the dialkylated product (54). Reduction of enone (54) with lithium aluminumhydride followed by acid hydrolysis of the ensuing ethoxy enol then afforded the 4,4-disubstituted cyclohexenone (55). Enone (55) was then subjected to carbomethoxylation using dimethylcarbonate followed by dehydrogenation with 2.3-dichloro-5,6-dicyanoqutnone to give the polyene cyclization precursor (16). Treatment of dienone (16) with zinc iodide in diethyl ether afforded bicyclic enone (20), the key intermediate of our synthetic strategy. Treatment of the sodium enolate of bicyclic enone (20) with methyl iodide then gave the bicyclic conjugated dienyl product (59) which was then subjected to reduction by lithium aluminumhydride and acidic workup to afford bicyclic dienone (73). Finally, catalytic hydrogenation of bicyclic dienone (73) using Wilkinson,s catalyst gave bicyclic enone (76), the advanced intermediate of our synthetic sequence.

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