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首页> 外文期刊>Chemistry: A European journal >Homoleptic lanthanide amides as homogeneous catalysts for alkyne hydroamination and the Tishchenko reaction
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Homoleptic lanthanide amides as homogeneous catalysts for alkyne hydroamination and the Tishchenko reaction

机译：均相镧系酰胺作为炔烃加氢胺化和Tishchenko反应的均相催化剂

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摘要

The homoleptic bis(trimethylsilyl)amides of Group 3 metals and lanthanides of the general type [Ln{N(SiMe3)(2)}(3)] (1) (Ln=Y, lanthanide) represent a new class of Tishchenko precatalysts and, to a limited extent, precatalysts for the hydroamination/cyclization of aminoalkynes. It is shown that I is the most active catalyst for the Tishchenko reaction. This contribution presents investigations on the scope of the reaction, substrate selectivity, lanthanide-ion size-effect, and kinetic/mechanistic aspects of the Tishchenko reaction catalyzed by 1. The turnover frequency is increased by the use of large-center metals and electron-withdrawing substrates. The reaction rate is second order with respect to the substrate. While donor atoms, such as nitrogen, oxygen, or sulfur, on the substrate decrease the turnover frequency, I shows a tolerance for a large number of functional groups. For the hydroamination/cyclization of aminoalkynes, 1 is less active than the well-known metallocene catalysts. On the other hand, 1 is much more readily accessible (one-step synthesis or commercially available), than the metallocenes and might therefore be an attractive alternative catalyst. [References: 84]
机译：一般类型[Ln {N（SiMe3）（2）}（3）]（1）（Ln = Y，镧系元素）的第3组金属和镧系元素的均衡双（三甲基甲硅烷基）酰胺代表一类新的Tishchenko预催化剂和在一定程度上限制了氨基炔烃的加氢胺化/环化反应的前催化剂。结果表明，I是Tishchenko反应最活跃的催化剂。这一贡献提供了对反应范围，底物选择性，镧系元素离子尺寸效应以及Tishchenko反应在1催化下的动力学/力学方面的研究。通过使用大中心金属和电子-取出基材。相对于基材，反应速率是二阶的。尽管基板上的供体原子（例如氮，氧或硫）降低了转换频率，但I对许多官能团均表现出耐受性。对于氨基炔烃的加氢胺化/环化反应，其活性比众所周知的茂金属催化剂低。另一方面，1比茂金属更容易获得（一步合成或可商购），因此可能是有吸引力的替代催化剂。 [参考：84]

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