Abstract
摘要本論文首先合成3a- 甲氧甲基- 雙環[3.3.0] 辛-1(6a)烯-2 -酮 (1-8), 4a -甲氧甲基- 雙環[4.3.0] 壬-7(1a) -烯-6- 酮(2-8), 4a -甲氧甲基 -雙環[4.4.0] 癸-1(8a)-烯-2-酮(3-6), 及4a-甲氧甲基- 雙環[4.3.0]壬-1(7a)- 烯-2- 酮(4-6) 等四種γ- 位置含甲氧甲基的雙環共軛烯酮, 並探討此四種烯酮化合物在稀濃度(0.01M) 的苯或異辛烷溶劑中, 以長波長(350nm) 或短波長(254nm) 光源引發的光化學反應.1-8 與2-8 為環戊烯酮類衍生物, 各以2-乙氧羰基的環戊酮及環己酮為起始物經七步合成, 產率各為23% 及40%, 3-6 與4-6 為環己烯酮類衍生物, 亦各由2-乙氧羰基的環己酮及環戊酮為起始物經六步合成, 產率各為56% 及28% .化合物1-8 在長波長照光, 得β- 碳擄氫環合產物及H-T 的cis-anti-cis雙聚合物,以短波長照光除得上述兩產物外另得α- 碳擄氫環合產物, 及H-T 的cis-anti-cis雙聚合物. 化合物3-6 在長波長照光, 得碳- 碳雙鍵轉移的β, γ- 不飽酮及雙環[3.3.1] 壬酮的二次光化產物, 在短波長照光, 除得上述二種產物外, 另得α- 碳擄氫環合產物及lumiketone重排產物. 化合物4-6 在長波長照光, 得β, γ- 不飽酮, lumiketone 重排, 及二次光化的雙環-[3.2.1]辛酮等三種產物, 在短波長照光, 得α-碳擄氫環合產物.由研究雙環烯酮的光化學反應結果, 得知不同類型化合物的光化學反應途徑不同, 環戊烯酮類衍生物1-8 與2-8 吸光後進行α- 碳與β- 碳擄氫環合反應及H-T 的cis-anti-cis雙聚合反應. 環己烯酮類衍生物3-6 與4-6 吸光後進行碳- 碳雙鍵去共軛, α- 碳擄氫環合及lumiketone重排等反應.///////AbstractFour compounds of bicyclic γ methoxymethyl-enones, 3a-methoxymethylbicyclo[3.3.0]oct-1(6a)-en-2-one(1-8), 4a-methoxymethylbicyclo[4.3.0]non-7(1a)-6one (2-8), 4a-methoxymethylbicyclo[4.4.0]dec-1(8a)-en-2-one(3-6) and 4a-methoxymethylbicyclo[4.3.0]non-1(7a)-en-2-one(4-6) were synthesized, and their photochemical reactions were studied.Compounds 1-8 and 2-8 are cyclopentenone derivatives which were prepared in seven steps from 2-ethoxycarbonylcyclopentanone (1-1) and 2-ethoxycarbonylcyclohexanone(2-1) in 23% and 40% total yields respectively, while compounds 3-6 and 4-6 were synthesized in six steps from 2-1 and 1-1 in 56% and 28% respectively.The photochemical reactions were carried out in the following manner. Solutions of enones(0.01M) in benzene or isooctane were irradiated with lightof 350nm or 254nm in a Rayonet reactor. When compound 1-8 was exposed tolight of 350nm, a product(1-9) generated via a β-carbon hydrogen abstraction and a H-T cis-anti-cis dimer(1-11) were obtained. When incident lightof wavelength 254nm was used, a product(1-10) formed via an α-carbon hydrogen abstraction was isolated in addition to 1-9 and 1-11. Irradiation ofcompound 2-8 at 254nm gave a H-T cis-anti-cis dimer(2-12), and products 2-9 and 2-10 produced via β-carbon and α-carbon bydrogen abstraction reactions respectively, while irradiation of 2-8 at 350nm yielded 2-11 and 2-12in addition to the above three products. When compound 3-6 was exposed tolight of 350nm, β,γ-unsaturated ketone 3-7, and a secondary photochemical product 3-10 were formed, while irradiation at 254nm afforded lumiketone3-8 and product 3-9 generated via an α-carbon hydrogen abstraction reaction in addition to 3-7 and 3-10. When compound 4-6 was irradiated with light of 350nm, β,γ-unsaturated ketone 4-7, lumiketone 4-8, and a secondary photochemical product 4-10 were produced, while irradiation of 4-6 at 254nm afforded mainly product 4-9 generated from an α-carbon hydrogen abstraction reaction.The above studies on the photochemical reactions of different bicyclic γ-methoxymethyl-enones showed that reactions take place via different reaction pathways depending on the structures of enones and the wave length of the incident light. Cyclopentenone derivatives 1-8 and 2-8 proceeded H-T cis-anti-cis dimerization, and α-carbon as well as β-carbon hydrogen abstraction reactions. However, cyclohexenone derivatives 3-6 and 4-6 proceededC-C double bond deconjugation reaction, α-carbon hydrogen abstraction reaction and lumiketone rearrangement.