銠與銅錯合物之催化環化反應:苯並呋喃與喹啉鹽類合成應用

Rhodium(III) and Copper(II)-Catalyzed Cyclization Reaction for the Synthesis of Benzofurans and Quinolinium Salts

陳韋禎

三組成反應 ； 吡啶喹啉鹽 ； 喹啉鹽 ； 疊氮芐 ； 碳-氫鍵活化 ； 苯並呋喃 ； 銅 ； Three compounents reaction ； pyridoquinolinium Salts ； Quinolinium Salts ； Benzylic Azides ； C-H bond activation ； Benzofurans ； copper

清華大學化學系所學位論文

2017年

博士

鄭建鴻

繁體中文

在本論文中分為三章，第一章為銠金屬碳-氫鍵活化反應應用於苯並呋喃衍生物之合成；第二、三章則是利用銅試劑與銅催化劑環化反應應用於平面四級銨鹽合成之研究而其中包含了吡啶喹啉鹽與芳基喹啉鹽。 苯並呋喃衍生物是一重要雜環結構，存在於許多天然物和生物活性分子中，另外也常作為有機材料中的重要結構單元。因此，在第一章中我們開發一個全新、極有效率與位向選擇性的方法，藉由利用銠(III)金屬催化劑的雙螯合輔助高位阻之碳-氫鍵活化苯酚來合成多取代的苯並呋喃。由於此反應具有相當優異的反應位向選擇性，因此此導引基將可允許金屬催化劑在未反應之鄰位再進行一次碳-氫鍵活化反應，進而做官能基化反應或環化反應。 在第二章中，我們發表了利用銅試劑對疊氮苄進行重排並與烯烴進行環化反應，根據不同的起始物會有三種不同類型的產物：吡啶喹啉鹽，二吡啶喹啉鹽和二喹啉。我們也證實此反應關鍵中間體為亞胺離子，而亞胺離子水解後產生甲醛可在參與二次環化反應，且反應涉及單電子轉移的氧化過程，因此具有二聚化、部分碳碳鍵斷裂之現象。由於亞胺中間體亦可由苯胺與甲醛反應合成，故我們也同時開發利用苯胺、甲醛與烯類進行三組成反應，成功合成相關吡啶喹啉鹽、二吡啶喹啉鹽和二喹啉衍生物。 而在第三章中我們延續第二章之研究興趣，我們開發一個銅催化氧化環化反應，利用苯胺、醛類與酮類合成芳基喹啉鹽，反應可能利用路易斯酸誘導的N-芳基亞胺離子和烯醇形式的酮的親核加成進行。同時炔類、烯類與丙烯酸酯皆可適用於該反應系統中，最後由於此反應的成功，我們也進一步將上一章當量反應改進為催化反應使反應更加有效率。

Chapter 1 Benzofuran derivatives are important molecules of heterocycles found in many natural and biologically active molecules and are often used as building blocks in organic materials.In chapter 1，a new strategy for the synthesis of highly substituted benzofurans from meta-substituted hydroxybenzenes and alkynes via a rhodium(III)-catalyzed activation of a sterically hindered C–H bond is demonstrated. A possible mechanism involving dual directing group assisted ortho C–H bond activation is proposed. Interestingly, the products we synthezied could support second C-H bond activation for further modification owing to the retention of O-methyloxime group attatched on them. Chapter 2 A novel copper-promoted multiple aza-[4 + 2] cycloaddition reaction of N-methyleneanilines generated in situ from benzylic azide and alkenes afforded quinolinium salts, biquinolinium salts, biquinolines or substituted quinolines depending on the substitution on the phenyl ring of benzylic azide.The reaction likely started by Lewis acidic CuII-assisted rearrangement of benzylic azide to N-methyleneaniline, followed by a [4 + 2] cycloaddition with alkene. Detailed mechanistic studies suggest that the biquinoline and biquinolinium salts are probably formed via radical processes. Besides the reaction of benzylic azides with alkenes, a one-pot multicomponent reaction of anilines, alkenes and formaldehyde was also investigated. Chapter 3 To continue our research result, we have successfully established an efficient copper-catalyzed aerobic oxidation of anilines, ketones and aldehydes to afford diverse functionalized N-aryl and -alkyl quinolinium salt in good to excellent yields.The reaction possibly proceeds via Lewis acid induced N-aryliminium ion and nucleophilic addition of enol formed of ketone. The cascade reaction is highly compatible with different π-components such as styrene, alkyne and activated alkenes as alternatives to ketones. Base on this study, we also improved the reaction in chapter 2 to an efficient copper-catalyzed aerobic oxidation reaction.

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