釕金屬錯合物與含異原子芳香炔丙醇反應之研究

Reactions of Ruthenium Complexes with Aromatic Enynes Containing Propargyl Alcohol and Heteroatom

馮怡蓁(Yi-Jhen Feng)

指導教授 ： 林英智

國立臺灣大學/理學院/化學研究所/博士(2013年)

https://doi.org/10.6342/NTU.2013.02336

摘要

本篇論文中，我們探討釕金屬錯合物與含異原子芳香烯炔丙醇之間的反應。在第一章中利用釕金屬錯合物(Cp(PPh3)2RuCl)與含氮原子的芳香烯炔丙醇(2、4)在室溫下進行環化反應，可得到金屬碳烯錯合物(3、5)帶有含氮芳香雜環。而釕金屬與含異噁唑芳香炔丙醇6在室溫下可獲得相似的金屬碳烯錯合物7，7為帶有胺基和酯基的萘環，此環化反應所產生的碳—碳鍵主要是來自異噁唑與被金屬活化之參鍵內的碳原子所形成。進一步將炔丙醇改變成炔丙胺與釕金屬反應，經由中間體釕亞乙烯基而得到釕金屬碳烯錯化合物9。釕金屬碳烯錯化合物(3、7、9)與三乙基胺在氧氣下室溫反應可得到帶有醛基之有機物(10、12、13)，此氧化反應的發生是先由三苯基磷游離形成一空位，氧氣分子經由金屬活化後進入此空配位在藉由三乙基胺而形成未觀察到的oxo-碳烯中間物，最後在與碳烯配基進行偶合反應而得到。
在第二章中，我們將氮原子置換成硫原子芳香烯炔丙醇以及有兩個甲基修飾在末端烯基14a與釕金屬在二氯甲烷下反應則是可以得到產物15a、16a以及17a。15a在二號碳位置上鍵結著六環的釕金屬亞乙烯基錯合物。我們推測此結果是經由釕金屬亞丙烯基形式的中間體在三號碳上進行環化反應而得。而16a是具有三苯基磷加成與碳硫螯合配位體C(H)=C(PPh3)C(OH)(C6H4S(CH2CCH=C(Me)2))的六員金屬含硫雜環錯合物。錯合物16a為親核性的三苯基磷加成在被金屬活化之參鍵的α碳原上所得到的產物。若相同反應下加入氟硼酸或是將金屬置換成(Cp(PPh3)2RuNCCH3)在二氯甲烷下反應則是可以得到單一產物碳烯錯化合物17a。親核性的硫原子加成在被金屬活化之參鍵的β碳原上所得到的產物。此錯合物與三乙基胺在氧氣下室溫反應可得到帶有醛基之有機物26a。相同反應在甲醇為溶劑室溫下則會得到連續兩次環化的釕金屬碳烯錯化合物20a 伴隨著16a、17a以及甲氧基加成的釕金屬亞乙烯基錯合物19a。而反應在40度時，除了16a、17a、20a生成之外，也得到另一個二次環化產物22a。將反應溫度提升到60度時22a上的配位基會從釕金屬上脫去而得到二次環化的有機物23a。形成二次環化的產物(20a、22a、23a)為經由第一次環化得到15a，接著末端烯基與釕金屬亞乙烯基的α碳進行環化反應而得到帶有三級碳陽原子的中間物，若經由連續的質子轉移會得到20a，若是溶液中的甲氧基加成到碳陽原子上則會得到22a，最後配位基從金屬上離去而得到23a。而相似的氧原子芳香烯炔丙醇14b與釕金屬反應也會得到相似的釕金屬亞乙烯基錯合物15b和二次環化的釕金屬碳烯錯化合物20b以及23b。而相較於末端烯基上沒有修飾甲基的烯炔丙醇14c與釕金屬在甲醇為溶劑時會產生在一號碳位置上鍵結著六環的金屬碳烯錯合物28c。
在第三章中，我們則是對末端烯基的內部碳上修飾甲基的含硫原子烯炔丙醇14d與釕金屬反應則是可以得到在二號碳位置上鍵結著七環的釕金屬亞乙烯基錯合物29d 和含硫雜環錯合物30d。而釕金屬亞乙烯基錯合物在乙腈溶液中可以被置換取代而得到烯炔化合物33d。而在甲醇溶液中則可以得到甲氧基加成的釕金屬亞乙烯基錯合物34d和連續環化的化合物35d伴隨著29d和30d的生成。將芳香烯炔丙醇化合物改成長碳鏈含氧原子的1,8-烯炔丙醇14e與釕金屬在二氯甲烷下反應可以得相似在二號碳位置上鍵結著七環的釕金屬亞乙烯基錯合物29e為主要產物。在不同的醇類為溶劑下與釕金屬反應也可以得到連續兩二環化的產物35e。而相較於末端烯基上沒有修飾甲基的烯炔丙醇14c與釕金屬在二氯甲烷下反應則不會有環化反應的發生。另外我們也發現利用乙腈配位的釕金屬錯合物(Cp(PPh3)2RuNCCH3+)與含硫原子烯炔丙醇14c和14d反應均會得到烯丙基重排的釕金屬碳烯錯化合物31。這些碳烯錯合物與三乙基胺在氧氣下室溫反應可得到帶有醛基之有機物37。以上的化學反應機制及釕金屬錯合物結構，可藉由氘取代實驗、二維核磁共振光譜儀及X光單晶繞射分析儀來作確認及鑑定。

關鍵字

釕 ； 吲哚口克唏 ； 苯并噻吩 ； 環化反應 ； 氧化反應 ； 三苯基磷加成反應

並列摘要

In this thesis, we investigated versatile reactivities of half-sandwiched ruthenium complexes with hetero-atom containing organic compounds. In chapter 1, the reactions of [Ru]Cl ([Ru] = Cp(PPh3)2Ru) with arylenynes 2, 4, 6, containing propargylic alcohol and ortho-substituted amine group on the aryl ring, and the reaction with enyne 8 containing a propargylic amine, are explored. For 2, the reactions give the carbene complexes 3, containing an indole group, which are formed through a new cyclization process between the nitrogen atom and the inner carbon of the triple bond. With an additional methylene group, enyne 4 reacts with [Ru]Cl to afford complex 5 with cyclized ligand. The reaction proceeds via a C-N bond forming process at Cβ in an intermediate where the triple bond is π-coordinated to the metal center. The reaction of [Ru]Cl with 6 with an isoxazole group affords the carbene complex 7 containing a naphthyl group at Cα with amine and ester substitutents. The reaction proceeds via a C-C bond formation between the isoxazole group and the inner carbon of the triple bond followed by a ring-opening of the isoxazole. By changing the propargylic alcohol to propargylic amine, the reaction of 8 first gives a vinylidene intermediate, followed by a retro-ene reaction to bring about cleavage of the aminoethanol group giving the carbene complex 9. Complexes 3, 7 and 9 react with oxygen in the presence of NEt3 at room temperature to afford indole-2-carbaldehyde 10, methyl 1-amino-3-formyl-2-naphthoate 12 and 4,4-dimethylhepta-2,6-dienal 13. Molecular O2 is likely activated by coordination to the metal center when one of the phosphine ligands dissociates. Then, NEt3 promotes the oxygenation process by reacting with the coordinated O2 to afford ONEt3 and possibly generate an unobserved oxo-carbene complex. Coupling of the oxo/carbene ligands followed by demetallation then yields the observed aldehyde product. The UV-Vis spectra of 3a, 7 and 9 consist of absorption bands with high extinction coefficient. From DFT calculations result, the visible light is found to populate the LUMO anti-bonding orbital of mainly Ru=C bond, therefore, weakening the Ru=C bond and promoting the oxygenation/demetallation reactions of carbene complexes.
In the chapter 2, Ru-assisted cyclizations of two enynes HC≡CCH(OH)(C6H4)X- CH2CH=CMe2 (X = S, 14a; X = O, 14b) each containing two terminal methyl groups on the olefinic parts yield in CH2Cl2 the vinylidene complexes 15a and 15b each with a new six-membered ring among other products. In MeOH, tandem cyclizations of 14a yield the organic compound 23a and the carbene complex 20a with a benzothiochromene ligand. Similar complexes 23b and 20b with benzochromene moieties were obtained from 14b with no other side product. Aromatization of 20a leads to the neutral product 24a, which is protonated to give the organic product 25a. The reactions yielding these thiochromene and chromene species may proceed via a first cyclization reaction between propargylic alcohol and alkene units giving vinylidene species followed by a second cyclization between Cα and the terminal carbon of the vinyl group. No C-C bond formation was observed in the reaction of [Ru]Cl with 14c, containing no methyl group in the olefinic part. The presence of methyl groups promotes sequential cyclization reactions of enynes, possibly via cationic species.
In the chapter 3, two aromatic S-enynes HC≡CCH(OH)(C6H4)SCH2C(R)=CH2 (14d, R = Me; 14c, R = H) containing olefinic groups with and without a methyl substitutent and an O-enyne HC≡CCH(OH)CMe2CH2OCH2C(Me)=CH2 14e also with an internal methyl group on the olefinic group but with no aromatic group are prepared. In the [Ru]Cl-induced ([Ru] = Cp(PPh)3Ru) reactions of 14d and 14e, the presence of the methyl group promotes cyclization reaction and their tandem cyclization is further promoted by the use of MeOH as a solvent. In the reaction of [Ru]Cl with 14d in CH2Cl2, three products 29d, 30d and 31d are isolated. Complex 29d, with a seven-membered ring bonded at Cβ of the vinylidene ligand, is formed via a C-C bond formation between two unsaturated groups in moderate yield. The metallacyclic complex 30d is formed via migration of PPh3 from metal onto the terminal carbon of alkyne and coordination of S atom yielding a chelating C,S-ligand. The carbene complex 31d is formed by S-addition to Cβ of the triple bond accompanied with migration of the allylic group from sulfur to the newly formed ring. In the reaction of 14d with [Ru]NCCH3+, 31d is isolated as a major product. The reaction of 14d with [Ru]Cl in MeOH generates the vinylidene complex 34d and the organic tandem cyclization product 35d in addition to 29d and 30d. Complex 34d is a product of formal addition of a methanol molecule to 29d. Compound 35d with a tricyclic-ring is formed possibly via sequential allenylidene/vinylidene cyclization followed by a nucleophilic addition of methoxide. The reaction of 14e with [Ru]Cl affords the vinylidene complex 29e in CH2-Cl2 via a similar cyclization process with no other side product. Heating complex 29e in CH3CN or treatment of 14e with 30 mol % [Ru]NCCH3+in CHCl3 at 60 °C for 1 day gave the cyclization organic enyne 33e. The reactions of 14e and 29e in CHCl3/MeOH lead to the organic tandem cyclization product 35e. For 14c, containing no methyl group in the olefinic part, no C-C bond formation was observed in the reaction with [Ru]Cl. All these reaction products are characterized by spectroscopic methods as well as elemental analysis. In addition, structures of three complexes 3a, 16a, 28c, 32d, 36d, and 38e are confirmed by X-ray diffraction analysis.

並列關鍵字

Ruthenium ； carbene ； vinylidene ； allenylidene ； indole ； oxygenation ； cyclization ； PPh3 addition ； enyne.

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