Dipyrrolyl precursors to bisalkoxide molybdenum olefin metathesis catalysts
Dipyrrolyl precursors to bisalkoxide molybdenum olefin metathesis catalysts
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DOI：
10.1021/ja0665904
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发表时间：
2006-12-20
影响因子：
15
通讯作者：
Hoveyda, Amir H.
中科院分区：
文献类型：
--
作者：
Hock, A. S.;Schrock, Richard R.;Hoveyda, Amir H.
在Mo(NR)(CHCMe2R')(OTf)(2)(DME) （OTf = OSO2CF3; R = 2,6-i- pr2c6h3, 1-adamantyl，或2,6- br -2-4- mec6h2； R' = Me或Ph）中加入2等量的吡啶锂，可产率较高的Mo(NR)(CHCMe2R')(NC4H4)(2)配合物。所有的化合物都可以很容易地从甲苯或戊烷和醚的混合物中重结晶，并且对空气和水分敏感。x射线结构2,6-diisopropylphenylimido物种显示它是一个不对称的二聚体,{莫(NAr) (syn-CHCMe2Ph)(η(5)-NC4H4)(η(1)-NC4H4)}{莫(NAr) (syn-CHCMe2Ph)(η(1)-NC4H4) 2},中氮埃塔(5)-pyrrolyl绑定到一个其他捐赠者莫莫行为。所有复合物上流动的NMR时间尺度在室温下,用一个对称的物种被观察到在NMR时间尺度在toluene-d 50摄氏度(8)。二聚体与PMe3 （Mo）或B(C6F5)(3) （eta(5)-NC4H4氮）反应生成高产的单体产物。它们还能与2个等量的单醇（如Me3COH或（CF3）(2)MeCOH）或1个等量的双酚或双酚迅速反应，生成2个等量的吡咯和双醇酸酯或二酸酯配合物，产率接近100%。
Addition of 2 equiv of lithium pyrrolide to Mo(NR)(CHCMe2R')(OTf)(2)(DME) (OTf = OSO2CF3; R = 2,6-i-Pr2C6H3, 1-adamantyl, or 2,6-Br-2-4-MeC6H2; R' = Me or Ph) produces Mo(NR)(CHCMe2R')(NC4H4)(2) complexes in good yield. All compounds can be recrystallized readily from toluene or mixtures of pentane and ether and are sensitive to air and moisture. An X-ray structure of a 2,6-diisopropylphenylimido species shows it to be an unsymmetric dimer, {Mo(NAr)(syn-CHCMe2Ph)(eta(5)-NC4H4)(eta(1)-NC4H4)}{Mo(NAr)(syn-CHCMe2Ph)(eta(1)-NC4H4)2}, in which the nitrogen in the eta(5)-pyrrolyl bound to one Mo behaves as a donor to the other Mo. All complexes are fluxional on the NMR time scale at room temperature, with one symmetric species being observed on the NMR time scale at 50 degrees C in toluene-d(8). The dimers react with PMe3 (at Mo) or B(C6F5)(3) (at a eta(5)-NC4H4 nitrogen) to give monomeric products in high yield. They also react rapidly with 2 equiv of monoalcohols (e.g., Me3COH or (CF3)(2)MeCOH) or 1 equiv of a biphenol or binaphthol to give 2 equiv of pyrrole and bisalkoxide or diolate complexes in similar to 100% yield.