Alkyne Activation by Electrophilic [(.eta.-C5Me5)Ru(NO)(R)]+ (R = Me, Ph, p-tolyl) Fragments: .beta.-Migratory Insertion, Isomerization, and Metallacycle Formation
Alkyne Activation by Electrophilic [(.eta.-C5Me5)Ru(NO)(R)]+ (R = Me, Ph, p-tolyl) Fragments: .beta.-Migratory Insertion, Isomerization, and Metallacycle Formation
复制标题
DOI：
10.1021/ja00100a015
复制
发表时间：
1994-10
影响因子：
15
通讯作者：
R. Burns;J. Hubbard
中科院分区：
文献类型：
--
作者：
R. Burns;J. Hubbard
Cp* Ru（NO）R的处理。2个配合物1-3与1当量的三氟甲磺酸（HOTf）反应，形成三氟甲磺酸基配合物Cp* Ru（NO）（R）（OTf）（4-6）（R= CH 3（1，4），C6 H 5（2，5），对甲苯基（3，6）; Cp*= r/* 12345 6-C5 Me 5）。5（C_（17）H_（20）NO_4SF_3RU）的X射线衍射数据：单斜晶系，空间群P_2_n，a= 10.041（2）k，B= 13.797（4）A，c= 15.113（3）A，jS= 106.68（2），Z= 4，R/R*= 4.50/3.37%。溶液中4-6中的三氟甲磺酸酯配体的解离可通过NMR光谱法检测。在THF中结合和游离三氟甲磺酸酯之间的平衡的AH/AS值对于4为（-2.1（1）kcal/mol）/（-9（1）eu），对于5为（-2.3（2）kcal/mol）/（-9（1）eu）。配合物4-6在CH_2Cl_2中的三氟甲磺酸酯解离被PhC= CPh的结合所捕获，导致最终通过β-迁移插入然后邻位取代O-芳基形成中性双烯环戊二烯产物8-10。8（C_（25）H_（27）-NORu）的X射线衍射数据：单斜晶系，空间群P_2\/c，a= 16.724（7）B= 7.274（2），c= 17.904（7），R/R_w = 102.26（3），Z= 4，R/R_w = 4.40/3.89%。10（C_（31）H_（31）NORU）的X射线衍射数据：单斜晶系，空间群P_2 ~ n，a= 9.597（2）k，B-22.577（4）k，c= 12.094（2）k，k = 101.34（2），Z= 4，R/Ry，= 4.84/4.57%。8的形成需要通过甲基/3-迁移插入到炔中形成的中间体-乙烯基复合物中的顺-反异构化。一个建议的机制为cis-trans-乙烯基异构化调用共振稳定通过反馈到[Cp* Ru（NO）]片段的-* 水平。当6与PhC= CPh反应时，只生成10，表明正位异构化比中间体乙烯基配体的顺反异构化快。质子化
Treatment of Cp* Ru (NO) R. 2 complexes 1-3 with 1 equiv of triflic acid (HOTf) leads to the formation of the triflato complexes Cp* Ru (NO)(R)(OTf)(4-6)(R= CH3 (1, 4), C6H5 (2, 5), p-tolyl (3, 6); Cp*= r/* 12345 6-C5Me5). X-ray data for 5 (C17H20NO4SF3RU): monoclinic space group P2\/n, a= 10.041 (2) k, b= 13.797 (4) A, c= 15.113 (3) Á, jS= 106.68 (2), Z= 4, R/R*= 4.50/3.37%. The dissociation of the triflate ligands in 4-6 in solution is detectable by NMR spectroscopy. The AH/AS values for equilibrium between bound and free triflate in THF are (-2.1 (1) kcal/mol)/(-9 (l) eu) for 4 and (-2.3 (2) kcal/mol)/(-9 (l) eu) for 5. Triflate dissociation from complexes 4-6 inCH2C12 is trapped by the binding of PhC= CPh, leading to the eventual formation of neutral ruthenacyclopentadiene products 8-10 by/3-migratory insertion followed by orthometallationof a 0-aryl group. X-ray data for 8 (C25H27-NORu): monoclinic space group P2\/c, a= 16.724 (7) Á, b= 7.274 (2) Á, c= 17.904 (7) Á, ß= 102.26 (3), Z= 4, R/Rw= 4.40/3.89%. X-ray data for 10 (C31H31NORU): monoclinic space group P2\/n, a= 9.597 (2) k, b-22.577 (4) Á, c= 12.094 (2) Á, ß= 101.34 (2), Z= 4, R/Ry,= 4.84/4.57%. Formation of 8 requires a cis-trans isomerization in the intermediate-vinyl complex formed by methyl/3-migratory insertion to the alkyne. A proposed mechanism for the cis-truns--vinyl isomerizationinvokes resonance stabilization through back-donation into the-* levels of the [Cp* Ru (NO) j fragment. Exclusive formation of 10 when 6 is treated with PhC= CPh shows orthometallation is rapid in comparisonto cis-trans isomerization of the intermediate-vinyl ligand. Protonation