1,3-Bis(<i>N</i>,<i>N</i>-dialkylamino)imidazolin-2-ylidenes: Synthesis and Reactivity of a New Family of Stable N-Heterocyclic Carbenes
作者:Manuel Alcarazo、Stephen J. Roseblade、Emma Alonso、Rosario Fernández、Eleuterio Alvarez、Fernando J. Lahoz、José M. Lassaletta
DOI:10.1021/ja0471119
日期:2004.10.1
The synthesis of stable 1,3-bis(N,N-dialkylamino)imidazolin-2-ylidenes was accomplished from readily available chiral bis-hydrazones after reduction or addition of PhMgCl, cyclization to imidazolinium salts, and treatment with KN(SiMe3)2. This strategy allows the obtention of free imidazolin-2-ylidenes and their Rh(COD)Cl complexes in enantiomerically pure form. The sigma-donor ability of dialkylamino-substituted
在还原或添加 PhMgCl、环化为咪唑啉盐并用 KN(SiMe3)2 处理后,从容易获得的手性双腙中合成稳定的 1,3-双(N,N-二烷基氨基)咪唑啉-2-亚基. 该策略允许以对映体纯形式获得游离咪唑啉-2-亚基及其 Rh(COD)Cl 配合物。发现二烷基氨基取代的二氨基卡宾的 σ 供体能力略高于烷基(芳基)类似物。