二茂鐵取代之釕金屬亞乙烯基錯合物的合成與鑑定

Synthesis and Characterization of Ferrocenyl Substituted Ruthenium Vinylidene Complexes

張立翰(Li-Hang Chang)

指導教授 ： 林英智

國立臺灣大學/理學院/化學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.02658

摘要

具有推電子基效應之取代基二茂鐵的釕金屬亞丙乙烯基錯合物 [Cp(L)2Ru=C=C=C(Fc)(H)][PF6] (L = PPh3, 2a; 1/2 dppe, 2b) 可經由釕金屬之三苯基磷或一，二-雙苯基磷乙烷、環戊二烯及氯配位之化合物 Cp(L)2RuCl (L = PPh3, 1/2 dppe) 在甲醇中和含有末端碳碳不飽和三鍵之鐵金屬乙炔醇類化合物 (FcCH(OH)C≡CH) 反應而得。釕金屬亞丙乙烯基錯合物與格林納試劑在丙乙烯基的γ碳上進行選擇性的親核加成反應，可以得到中性釕金屬之乙炔基錯合物 3a-3a’ Cp(L)2Ru-C≡CCH(Fc)R (Fc = (η5-C5H4)Fe(Cp), L = PPh3, R = CH2CH=CH2, 3a; R = CH2C≡CH, 3b; R = CH2C(CH3)=CH2, 3c; L = 1/2 dppe, R = CH2CH=CH2, 3a’)。一系列的中性釕金屬之乙炔基錯合物可進行氫化反應而得到陽離子釕金屬亞乙烯基錯合物 4a-4a’ [Cp(L)2Ru=C=CHCH(Fc)R]+ (L = PPh3 ,R = CH2CH=CH2, 4a; R = CH2C≡CH, 4b; R = CH2C(CH3)=CH2, 4c; L = 1/2 dppe, R = CH2CH=CH2, 4a’)。其中以錯合物4a具有獨特的反應性。當4a在室溫中溶解於二氯甲烷或甲醇溶劑時，會慢慢進行一種前所未見的轉換。它首先會產生骨架重排然後再進行β碳與二茂鐵上的環戊二烯之碳碳鍵生成，也就是進行一種Friedel-Craft 反應而生成一個不同的陽離子釕金屬亞乙烯基錯合物6a [Cp(PPh3)2Ru=C=C-CH2C(Fc)(H)CH=CH2][BF4]。
當另一個釕金屬亞乙烯基錯合物[Cp(PPh3)2Ru=C=CHC(Fc)(Ph)CH2CH=CH2] [BF4] 4d在室溫中溶解於二氯甲烷或甲醇溶劑時，也會進行類似於4a的反應，進而產生分子內環化的反應之產物[Cp(PPh3)2Ru=C=C-CH2C(Fc)(Ph)CH=CH2] [BF4] 6d。6a與6d之不同處在於：前者是二茂鐵上未取代的環戊二烯與β碳相接；後者是二茂鐵上已取代的環戊二烯與β碳相接。導致這樣不同的結果歸咎於同在一個碳上二茂鐵與苯環之間的立體阻礙：由於在4d中在四號碳上有苯環存在的因素，迫使二茂鐵上已取代的環戊二烯與β碳更加靠近，以利於進行Friedel-Craft 反應。
另一方面，我們也發展了一些利用鋨金屬之三苯基磷、環戊二烯及溴配位之化合物的催化反應(Cp(PPh3)2OsBr)：將一系列的二茂鐵取代之一，五-烯炔類化合物催化成對應的二茂鐵取代之芳香族羥基化合物(arylferrocenes)

關鍵字

二茂鐵 ； 亞乙烯基 ； 釕金屬 ； 環化反應

並列摘要

Ferrocenyl-substituted allenylidene complexes [Cp(L)2Ru=C=C=C(Fc)(H)][PF6] (L = PPh3, 2a; 1/2 dppe, 2b) were prepared by treatment of a methanol solution of Cp(L)2RuCl (L = PPh3, 1/2 dppe) with the propargylic alcohol 1-ferrocenyl-2-propyn-1-ol in the presence of NH4PF6.
Reaction of 2a-b with Grignard reagents RMgBr in THF yielded the neutral acetylide complexes 3a-3a’ Cp(L)2Ru-C≡CCH(Fc)R (Fc = (η5-C5H4)Fe(Cp), L = PPh3, R = CH2CH=CH2, 3a; R = CH2C≡CH, 3b; R = CH2C(CH3)=CH2, 3c; L = 1/2 dppe, R = CH2CH=CH2, 3a’). Complexes 3a-3a’ underwent protonation reactions affording the corresponding vinylidene complexes 4a-4a’ [Cp(L)2Ru=C=CHCH(Fc)R]+ (L = PPh3 ,R = CH2CH=CH2, 4a; R = CH2C≡CH, 4b; R = CH2C(CH3)=CH2, 4c; L = 1/2 dppe, R = CH2CH=CH2, 4a’).
Interestingly, the vinylidene complex 4a has specific reactivity owing to the presence of the ferrocenyl group with a redox-active moiety and strong electron donating ability. When complex 4a is dissolved in dichloromethane or methanol at room temperature, it gradually underwent an unprecedented transformation. A skeleton rearrangement of 4a, followed by a C-C bond formation of Cβ and the Cp of the ferrocene was found to produce the vinylidene complex [Cp(PPh3)2Ru=C=C-CH2C(Fc)(H)CH=CH2][BF4] 6a. Such a transformation is thought to be a Friedel-Craft alkylation.
When vinylidene complex [Cp(PPh3)2Ru=C=CHC(Fc)(Ph)CH2CH=CH2] [BF4] 4d which is synthesized by Yeh in our laboratory is dissolved in dichloromethane or methanol at room temperature, it also undergoes the similar reaction as 4a. The vinylidene complex 4d gradually transforms to the intermediate 5d and finally converts to the intramolecular cyclization product [Cp(PPh3)2Ru=C=C-CH2C(Fc)(Ph)CH=CH2][BF4] 6d. Interestingly, there is an apparent difference between 6a and 6d. For 6a, the ‘unsubstituted’ Cp group attacks Cβ of the vinylidene ligand. And on the other hand, for 6d, it is the ‘substituted’ Cp, which is attached to C4, that attacks Cβ of the vinylidene ligand. It is thought that there is a steric hindrance between the ferrocenyl group and the phenyl group that drives the substituted Cp of the ferrocenyl group to move close to the Cβ, therefore, processing the Friedel-Craft alkylation

We herein report the transformation of ferrocenyl substituted propargyl alcohol to arylferrocene catalyzed by Cp(PPh3)2OsBr. 1-ferrocenyl-2-propyn-1-one (7) is a useful and convenient starting material to produce a variety of 1,5-enynes, which can be cyclized to form the corresponding arylferrocenes by the osmium complex in good yield without the use of toxic reagent and less preliminary laborious preparation.
The easy preparation of these ferrocenyl substituted propargyl alcohol, their high solubility in organic solvents, indefinite shelf life, stability towards air make them ideal compounds for the synthesis of monosubstituted arylferrocenes.

並列關鍵字

Ferrocenyl ； Vinylidene ； Ruthenium ； Friedel-Craft ； Cyclization

參考文獻

2. Bruce, M. I. Chem. Rev. 1991, 91, 197-257.

6. Abbott, S.; Davies, S. G.; Warner, P. J. Organomet. Chem. 1983, 246, C65-C68.

9. King, R. B.; Saran, M. S. J. Chem. Soc. Chem. Commun. 1972, 19, 1053-1072.

10. Cadierno, V.; Gamasa, M. P.; Gimeno, J. Coord. Chem. Rev. 2004, 248, 1627-1657.

11. Ozawa, F. Coord. Chem. Rev. 2004, 248, 1702-1715.