Herzon Seth B, Hartwig John F
Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
J Am Chem Soc. 2008 Nov 12;130(45):14940-1. doi: 10.1021/ja806367e. Epub 2008 Oct 21.
The intermolecular addition of the alpha-C-H bonds of unactivated dialkylamines to unactivated olefins in the presence of the chloro amido complex [TaCl3(NEt2)2]2 (2) is described. This process forms the branched insertion products in high yields (up to 96%) and selectivities, and represents a rare example of an intermolecular amine-olefin coupling reaction that does not require preactivation of either substrate. The reaction is shown to encompass the addition of the primary C-H bonds in linear- and branched-methylamines, as well as secondary C-H bonds in higher dialkylamines. The related chloroanilido complex [TaCl3(NMePh)2]2 (4) is also shown to catalyze the addition of N-alkyl-arylamines to olefins at temperatures as low as 90 degreesC. 1H NMR spectroscopy, identification of the catalyst structure, and deuterium-labeling experiments all suggest that reactions catalyzed by 2 and 4 occur by turnover-limiting generation of an eta2-imine complex. These labeling studies also imply that more favorable partitioning of the eta2-imine complex toward reaction with alkene versus regeneration of the starting bis-amido complex accounts for the higher reactivity of the mixed halide amido catalyst versus a homoleptic amido complex.
本文描述了在氯代酰胺配合物[TaCl3(NEt2)2]2 (2)存在下，未活化的二烷基胺的α-C-H键与未活化的烯烃进行分子间加成反应。该过程能以高产率（高达96%）和高选择性形成支链插入产物，是分子间胺-烯烃偶联反应中罕见的例子，该反应无需对任何一种底物进行预活化。该反应表明包括直链和支链甲胺中的伯C-H键以及高级二烷基胺中的仲C-H键的加成。相关的氯代苯胺基配合物[TaCl3(NMePh)2]2 (4)也被证明在低至90℃的温度下能催化N-烷基芳基胺与烯烃的加成反应。1H NMR光谱、催化剂结构鉴定以及氘标记实验均表明，由2和4催化的反应是通过η2-亚胺配合物的周转限制生成而发生的。这些标记研究还表明，η2-亚胺配合物与烯烃反应相对于起始双酰胺配合物再生的更有利分配解释了混合卤化物酰胺催化剂相对于均配酰胺配合物具有更高的反应活性。
