Unexpected migratory insertion reactions of M(alkyl)2 (M=Zn, Cd) and diamidocarbenes.
Unexpected migratory insertion reactions of M(alkyl)2 (M=Zn, Cd) and diamidocarbenes.
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DOI：
10.1002/chem.201406406
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发表时间：
2015-02
期刊：
影响因子：
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通讯作者：
L. R. Collins;Gabriele Hierlmeier;M. Mahon;Ian M. Riddlestone;M. Whittlesey
中科院分区：
文献类型：
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作者：
L. R. Collins;Gabriele Hierlmeier;M. Mahon;Ian M. Riddlestone;M. Whittlesey
自由二胺碳烯（DACs）的亲电特性使它们能够激活小分子（如NH3和P4）中的惰性键。本文中，我们报道了金属配位dac也表现出亲电性，受到Zn和Cd二烷基前体的攻击，产生迁移插入产物[(6-MesDAC-R)MR] （M=Zn, Cd； R=Et, Me; Mes=mesityl）。这些物种是通过光谱表征的中间体[(6-MesDAC)MR2]形成的，表现出迁移插入障碍，其顺序为MR2 = ZnEt2 < ZnMe2 < CdMe2。化合物[(6-MesDAC-Me)CdMe]表现出有限的稳定性，通过明显的β-H消除途径沉积Cd金属。这些结果引起了人们对二胺羰基作为配体在含亲核配体（M-R, M-H）金属的催化反应中的适用性的怀疑。
The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH3 and P4 . Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6-MesDAC-R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6-MesDAC)MR2 ], exhibiting barriers to migratory insertion which increase in the order MR2 = ZnEt2 < ZnMe2 < CdMe2 . Compound [(6-MesDAC-Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β-H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M-R, M-H).