Adamantyl-Substituted <i>N</i>-Heterocyclic Carbene Ligands in Second-Generation Grubbs-Type Metathesis Catalysts
作者:Maarten B. Dinger、Piotr Nieczypor、Johannes C. Mol
DOI:10.1021/om034062k
日期:2003.12.1
The N-heterocyclic carbene (NHC) ligands H2IAd (H2IAd = 1,3-di(1-adamantyl)-4,5-dihydroimidazol-2-ylidene) and H2IAdMes (H2IAdMes = 1-(1-adamantyl)-3-mesityl-4,5-dihydroimidazol-2-ylidine) were prepared and treated with [RuCl2(CHPh)(PCy3)2] (1). While H2IAd failed to react with 1, H2IAdMes readily produced [RuCl2(CHPh)(H2IAdMes)(PCy3)] (7). Only a single isomer of 7 was formed, this being that with
的Ñ -杂环卡宾(NHC)配体ħ 2 IAD(H 2 IAD = 1,3-二(1-金刚烷基)-4,5-二氢咪唑-2-亚基)和H 2个IAdMes(H 2 IAdMes = 1-(制备1-金刚烷基)-3-甲磺酰基1-4,5-二氢咪唑-2-基吡啶,并用[RuCl 2(CHPh)(PCy 3)2 ](1)处理。虽然H 2 IAd无法与1反应,但H 2 IAdMes容易产生[RuCl 2(CHPh)(H 2 IAdMes)(PCy 3)](7)。只有7个异构体通过X-射线结构证实,其形成的是异丁烯环位于亚苄基部分上方。发现配合物7仅是非常差的烯烃复分解催化剂,这可能是1-金刚烷基部分朝着亚苄基的反式位置赋予的过度空间拥挤的结果。