釕金屬錯合物與芳香族分子進行分子內環化反應
之研究:碳-碳鍵與碳-氧鍵的斷裂與形成

我們修飾釕金屬錯合物Cp(PPh3)2RuCl和一系列苯環上一端帶有末端炔丙醇而另一端為烯類的有機化合物的環化反應。保留末端炔丙醇而將另一端的烯類官能基轉變成環氧基與並對它進行開環反應，而得到一種同時具有離去基和親電子基之官能基的有機化合物，並利用此兩種有機化合物和釕金屬錯合物反應。首先將烯基改為環氧基，利用此化合物與釕金屬錯合物Cp(PPh3)2RuCl的反應中在以KF為鹽類，甲醇為溶劑的情況下，得到金屬錯合物7，但是有趣的是當把鹽類從KF換為KPF6並保持其他相同的反應條件時，則最終產物從金屬錯合物7變成了金屬錯合物11。推測在這主要藉由釕金屬返鍵結到Cα上的特性，進行環化反應，而這樣的例子，也間接地證明了鹽類對金屬反應性的影響。在第二種配位基中, 延續烯基改為環氧基的修飾，製備一系列苯環上一端帶有末端炔丙醇而另一端同時具有親核基和親電子基的有機物。此系列有機物與釕金屬錯合物Cp(PPh3)2RuCl在以甲醇為溶劑的情況下，進行反應。有機物中的末端炔丙醇會跟釕金屬配位並進行脫水，而形成釕金屬亞丙二烯基錯合物的中間體，此時由於配位基鄰位的羥基具有親核的性質，再加上Cγ本身略帶微正電，因此十分容易去進行分子內環化反應，而形成一個丙炔釕金屬錯合物中間體。而此中間體由於受到附近有離去基的影響，形成後相當地不穩定，因此它會經由一個碳-碳鍵的生成，迅速脫去離去基，變成一個帶有三個環的陽離子釕金屬亞乙烯基錯合物。新的生成物用NMR光譜的鑑定上，此外也使用二維光譜如COSY, 1H,13C-HSQC, HMBC提供生成物中形成了三個環的結構的證據。質譜也提供相互一致的訊號，作為決定錯合物結構的證據。

關鍵字

釕金屬；擴環反應；含氧五環；含氧七環；環化反應

並列摘要

The reaction of [Ru]Cl ([Ru] = Cp(PPh3)2Ru) with 1,6-enyne compounds, in which the triple bond of enyne is associated with a propargylic alcohol and the olefinic group of enyne having various substituted methyl groups is modified by changing the olefinic group to contain other functional groups, exhibits an intramolecular cyclization involving C-O bond formation and C-C bond formation. When the olefinic group is converted to give the epoxide with no substituted methyl group, the reactions of the substrate with [Ru]Cl in the presence of KF in MeOH at 50oC for one day afford the acetylide complex. This reaction takes place at the propargylic alcohol first giving the allenylidene complex as an intermediate, then MeOH attacks Cγ as a nucleophilic group via a C-O bond information to form the acetylide complex as a final product. Interestingly, by changing KF into KPF6 under the same condition, the acetylide complex continues to proceed an intramolecular cyclization at Cβ to open the epoxide group to yield the disubstituted vinylidene complex. This C-C bond formation occurs at Cβ, possibly assisted by the presence of KPF6, to form the disubstituted vinylidene complex. The olefinic part of enyne substrate is also transformed to a hydroxy group as a nucleophile and a bromide group as a good leaving group. Reactions of these compounds with [Ru]Cl in the presence of KF in MeOH proceed tandem cyclization to form tricyclic complexes. The first step of the reaction involves dehydration of the propargylic group leading to the allenylidene complex. Then an intramolecular nucleophilic addition of the hydroxyl group to Cγ of the allenylidene ligand results in the acetylide complex as an intermediate, which is only transient possibly due to the presence of a near-by electrophilic group. Thus the second cyclization via a C-C bond formation cleaves the C-Br bond to form the tricycle ruthenium complex. This reaction proceeds by a cyclization reaction involving a propargylic alcohol, a nucleophilic group and an electronphilic group to form the vinylidene ligand with a tricyclic ring on the metal. The structures of the newly formed products are supported by their 1H, 31P and 13C NMR spectra. In order to gain further information to support the structure of these complexes, 2-D NMR spectra such as 1H,1H-COSY, 1H,13C-HSQC, 1H,13C-HMBC are also employed. These data indirectly corroborate the tandem cyclizations at Cβ and Cγ of the allenylidene ligand forming tricyclic complexes.

並列關鍵字

Ruthenium ； acetylide ； vinylidene ； allenylidene ； phosphonium acetylide ； cyclization

參考文獻

1.(a)Ipaktschi, J.; Mirzaei, F.; Reimann, K.; Beck, J.; Serafin, M.; Organometallics. 1998, 17, 5086–5090. (b) Chung, C. P.; Chen, C. C.; Lin, Y.-C.; Liu, Y. H.; Wang, Y. J. Am. Chem. Soc. 2009, 131, 18336–18375.

11.Wulff, W. D.; Yang, D. C.; Murray, C. K. Pure appl. Chem. 1988, 60, 137– 144.

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37.Lin, Song.; Song, C. X.; Cai, G. X.; Wang, W. H.; Shi, Z. J. J. Am. Chem. Soc. 2008, 130 (39), 12901–12903.

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釕金屬錯合物與芳香族分子進行分子內環化反應之研究:碳-碳鍵與碳-氧鍵的斷裂與形成

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