Zincocene and Dizincocene N-Heterocyclic Carbene Complexes and Catalytic Hydrogenation of Imines and Ketones
作者:Phillip Jochmann、Douglas W. Stephan
DOI:10.1002/chem.201402875
日期:2014.7.1
N‐heterocyclic carbene (NHC) adducts Zn(CpR)2(NHC)] (CpR=C5HMe4, C5H4SiMe3; NHC=ItBu, IDipp (Dipp=2,6‐diisopropylphenyl), IMes (Mes=mesityl), SIMes) were prepared and shown to be active catalysts for the hydrogenation of imines, whereas decamethylzincocene [ZnCp*2] is highly active for the hydrogenation of ketones in the presence of noncoordinating NHCs. The abnormal carbene complex [Zn(OCHPh2)2(aItBu)]2
N-杂环卡宾(NHC)加合物Zn(Cp R)2(NHC)](Cp R = C 5 HMe 4,C 5 H 4 SiMe 3; NHC = I t Bu,IDipp(Dipp = 2,6-二异丙基苯基) ),IMes(Mes = mesityl),SIMes)制备后显示为亚胺加氢的活性催化剂,而十甲基锌茂茂[ZnCp * 2 ]在非配位NHC的存在下对酮的氢化具有高活性。异常卡宾配合物[Zn(OCHPh 2)2(aI t Bu)] 2是由I t的自发重排形成的二苯甲酮不完全氢化过程中的Bu配体。介绍了两种分离的Zn I加合物[Zn 2 Cp * 2(NHC)](NHC = I t Bu,SIMes),并根据13 C NMR光谱和X射线衍射实验将其表征为弱加合物。讨论了用H 2还原[ZnCp * 2 ]以获得[Zn 2 Cp * 2 ]的机制建议。