C-H bond activation of hydrocarbons by an imidozirconocene complex.
C-H bond activation of hydrocarbons by an imidozirconocene complex.
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DOI：
10.1021/ja0385944
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发表时间：
2004-02
影响因子：
15
通讯作者：
Helen M. Hoyt;F. Michael;R. Bergman
中科院分区：
文献类型：
--
作者：
Helen M. Hoyt;F. Michael;R. Bergman
Monomeric imidozirconocene complexes of the type Cp2(L)Zr=NCMe3 (Cp = cyclopentadienyl, L = Lewis base) have been shown to activate the carbon-hydrogen bonds of benzene, but not the C-H bonds of saturated hydrocarbons. To our knowledge, this singularly important class of C-H activation reactions has heretofore not been observed in imidometallocene systems. The M=NR bond formed on heating the racemic ethylenebis(tetrahydro)indenyl methyl tert-butyl amide complex, however, cleanly and quantitatively activates a wide range of n-alkane, alkene, and arene C-H bonds. Mechanistic experiments support the proposal of intramolecular elimination of methane followed by a concerted addition of the hydrocarbon C-H bond. Products formed by activation of sp2 C-H bonds are generally more thermodynamically stable than those formed by activation of sp3 C-H bonds, and those resulting from reaction at primary C-H bonds are preferred over secondary sp3 C-H activation products. There is also evidence that thermodynamic selectivity among C-H bonds is sterically rather than electronically controlled.
