Ir-Catalysed Asymmetric Allylic Substitutions with Cyclometalated (Phosphoramidite)Ir Complexes-Resting States, Catalytically Active (π-Allyl)Ir Complexes and Computational Exploration
Ir-Catalysed Asymmetric Allylic Substitutions with Cyclometalated (Phosphoramidite)Ir Complexes-Resting States, Catalytically Active (π-Allyl)Ir Complexes and Computational Exploration
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DOI：
10.1002/chem.200903465
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Helmchen, Guenter
中科院分区：
文献类型：
--
作者：
Raskatov, Jevgenij A.;Spiess, Stephanie;Helmchen, Guenter
研究了亚磷酰胺环化反应生成的铱催化剂催化烯丙基取代反应的机理。通过P-31 NMR光谱法测定静息态，得出环化过程是可逆的结论。一种新的，一锅法制备（π-烯丙基）铱配合物的程序开发，这些配合物的特征在于通过X-射线晶体结构分析和光谱数据。它们是烯丙基取代反应的完全活性催化剂。对烯丙基络合物、烯丙基取代过渡态和产物烯烃络合物的密度泛函计算给出了进一步的机理认识。
Mechanistic aspects of allylic substitutions with iridium catalysts derived from phosphoramidites by cyclometalation were investigated. The determination of resting states by P-31 NMR spectroscopy led to the conclusion that the cyclometalation process is reversible. A novel, one-pot procedure for the preparation of (pi-allyl)Ir complexes was developed, and these complexes were characterised by X-ray crystal structure analyses and spectral data. They are fully active catalysts of the allylic substitution reaction. DFT calculations on the allyl complexes, transition states of the allylic substitution and product olefin complexes gave further mechanistic insight.