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  • 學位論文

有機金屬鉑、金應用於順式烯醛及烯炔類分子進行環化反應之研究

Platinum and Gold Catalyzed Cyclization of cis-2,4-Diene-1-als and Enynes

指導教授 : 劉瑞雄

摘要


本論文分成三個部分,主要是探討過渡金屬金和鉑催化順式二烯醛和烯炔類等有機分子進行環化反應。 在第一部份中,我們了解順式二烯醛在目前有機反應是相當有用的,為了提升順式二烯醛合成上的價值,我們報導了利用金金屬催化順二烯醛分子進行環化反應,其中會伴隨著去氧基現象及具有位向控制的親核基加成反應,在反應中添加不同的親核基可生成具有兩個碳-氫、碳-氧、碳-氮、碳-硫和碳-碳鍵新型的環戊烯結構。此外,這個新方法可以運用各種適當的親核基運用在順式二烯醛環化反應中,可以經由多種變化的環化反應在一步的反應中建構出複雜的多環化合物。 第二部分中,在第一章所發現新穎的金金屬催化順式二烯醛的反應中,可以觀察到兩次碳陽離子的形成能夠變化多樣的反應形式來建構出複雜的分子骨架。之前,我們探討分子間類型的順式烯醛去氧基環化反應。 在此,我們將焦點轉移至此新反應延伸至分子內環化反應中,更進一步在催化反應中添加親核基當作捕捉試劑,可以順利的進行分子內環化反應形成複雜的環氧化合物。值得注意的是,成功的運用我們所開發新穎的分子內環化反應來建構天然物Brazilin的架構。可利用我們設計的順式烯醛來進行分子內環化反應,以建構Brazilin的架構中B和C環,成功合成出Brazilane化合物,也能經由修飾順式烯醛的取代基合成出多種Brazilane衍生物。 第三部分我們以三氯化金 (AuCl3)、二氯化鉑 (PtCl2) 和釕金屬錯合物 (Ru-complex) 為催化劑,催化具有6,6-雙取代的3,5-雙烯-1-炔類化合物作環化反應,此反應會經由1,7-氫轉移的過程來完成反應,此外,我們也藉由改變1號和6號碳上的為苯環或羰基取代基而增加其反應效率,而1,7-氫轉移的現象類似“質子性”氫的轉移,其反應效率決定於七號氫上的酸性。 在反應中我們發現添加三氯化金、二氯化鉑和釕金屬錯合物為催化劑可以大幅提升環化的效率,藉由1,7-氫轉移的現象我們可以導入各種不同官能基取代於烯炔受質上,有助於未來在有機合成上的應用。

關鍵字

金金屬 環化反應 催化反應

並列摘要


Chapter I   In this chapter, cis-2,4-diene-1-al functionality are readily available in organic synthesis. To pursue the synthetic value of cis-2,4-diene-1-al, we report a novel gold-catalyzed deoxygenated cyclization of cis-2,4-diene-1-al via regiocontrolled 1,4-addition of two nucleophiles, which allows formation of two C-X bonds (X = H, O, S, N, C) on the newly generated cyclopentene framework. Notably, this approach enables a one-step construction of complex polycyclic frameworks via diversified annulation of cis-2,4-diene-1-al with suitable nucleophiles. Chapter II In this novel gold catalysis, the dication equivalence of cis-2,4-diene-1-al enables diversified version to construct complex framework. So far, we described the intermolecular versions of cyclization deoxygenated reaction. At this point we turned our attention to apply this newly developed reaction to its intramolecular version. We further extended this catalytic cyclization in presence of nuclophiles as trapping reagent, intramolecular cyclization proceeded smoothly to give complex oxacyclic compounds. One remarkable, We have successfully applied our novel intramolecular cyclization protocol for constructed Brazilin skeleton. This synthesis started by synthesis diene-aldehyde substrate, and based on intramolecular cyclization establish B/C ring junction successful synthesis Brazilane and Brazilane derivatives naturally. Chapter III Chapter III describes the feasibility of thermal and catalytic cyclization of 6,6-disubstituted 3,5-dien-1-ynes via a 1,7-hydrogen shift. We first studied the thermal efficiency of model molecules via alternation of the C(1)-phenyl and C(6)-carbonyl substituents of substrates; we concluded that the observed 1,7-hydrogen shift is nearly a “protonic” hydrogen shift. This structure-activity relationship indicates that □-alkyne activators can catalyze suitably functionalized 3,5-dien-1-ynes efficiently although their thermal yields were generally low. We prepared various 6,6-disubstituted 3,5-dien-1-ynes bearing either a phenyl or carbonyl group, and found their thermal cyclizations to be greatly enhanced by PtCl2, AuCl3, Ru-complex catalysts to confirm our hypothesis: the C(7)-H acidity of 3,5-dien-1-ynes is crucial for thermal cyclization.

參考文獻


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