Mechanistic Aspects of the Reactions of Bis(pentafluorophenyl)borane with the Dialkyl Zirconocenes Cp2ZrR2 (R = CH3, CH2SiMe3, and CH2C6H5)
Mechanistic Aspects of the Reactions of Bis(pentafluorophenyl)borane with the Dialkyl Zirconocenes Cp2ZrR2 (R = CH3, CH2SiMe3, and CH2C6H5)
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双（五氟苯基）硼烷与二烷基二茂锆 Cp2ZrR2（R = CH3、CH2SiMe3 和 CH2C6H5）反应的机理
DOI：
10.1021/om9802313
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发表时间：
1998
期刊：
影响因子：
2.8
通讯作者：
M. Zaworotko
中科院分区：
文献类型：
--
作者：
R. Spence;W. Piers;Yimin Sun;M. Parvez;L. MacGillivray;M. Zaworotko
双（五氟苯）硼烷与简单二烷基锆二辛化合物Cp2ZrR2 （R = CH3, CH2SiMe3, CH2Ph）通过初始烷基/氢化物交换反应生成“Cp2Zr(H)R”和RB(C6F5)2。然后，根据是否存在HB(C6F5)2的进一步等效物，遵循两个反应路径。如果存在，HB(C6F5)2与新形成的Zr−H部分反应生成二氢硼酸化合物，最终生成Cp2Zr[(μ-H)2B(C6F5)2] 2,1和RB(C6F5)2的等量物。化合物1用x射线晶体学进行了表征。在HB(C6F5)2不存在的情况下，烷基/氢化物交换反应产物消除RH，生成硼稳定的烷基烯化合物Cp2Zr(μ-CH2)[(μ-H)B(C6F5)2]， 2和Cp2Zr{η3-CH(C6H5)[(μ-H)B(C6F5)2], 4。后一种化合物生成干净，产率92%，并用x射线晶体学对其进行了表征。对这些部分氘化化合物反应的机理研究表明，烷基/氢化物交换过程是可逆的，并通过一个渐进的过程发生。
The reactions of bis(pentafluorophenyl)borane with simple dialkyl zirconocenes Cp2ZrR2 (R = CH3, CH2SiMe3, CH2Ph) proceed via initial alkyl/hydride exchange to yield “Cp2Zr(H)R” and RB(C6F5)2. Two reaction paths are then followed depending on whether further equivalents of HB(C6F5)2 are present or not. If present, HB(C6F5)2 reacts with the newly formed Zr−H moiety to form dihydridoborate compounds, ultimately yielding Cp2Zr[(μ-H)2B(C6F5)2]2, 1, and 2 equiv of RB(C6F5)2. Compound 1 was characterized by X-ray crystallography. In the absence of more HB(C6F5)2, the products of alkyl/hydride exchange react to eliminate RH and produce the borane-stabilized alkylidene compounds Cp2Zr(μ-CH2)[(μ-H)B(C6F5)2], 2, and Cp2Zr{η3-CH(C6H5)[(μ-H)B(C6F5)2]}, 4. The latter compound is formed cleanly in 92% yield and was characterized by X-ray crystallography. Mechanistic studies on these reactions involving partially deuterated compounds reveal that the alkyl/hyride exchange process is reversible and takes place via a stepw...