Zwitterionic Iridium Complexes with P,N-Ligands as Catalysts for the Asymmetric Hydrogenation of Alkenes
作者:Axel Franzke、Andreas Pfaltz
DOI:10.1002/chem.201003314
日期:2011.4.4
Several zwitterionic iridium complexes based on chiral P,N‐ligands with imidazoline or oxazoline donors and anionic tetraarylborate or aryltrifluoroborate substituents have been synthesized. The corresponding cationic analogues have also been prepared, to evaluate the effect of the covalent linkage between the anion and the cationic metal complex in catalytic reactions. The respective pairs of structurally
已经合成了几种基于手性P,N-配体与咪唑啉或恶唑啉供体以及阴离子四芳基硼酸酯或芳基三氟硼酸酯取代基的两性离子铱配合物。还制备了相应的阳离子类似物,以评估阴离子与阳离子金属络合物之间的共价键在催化反应中的作用。已经比较了各对结构类似的预催化剂在未官能化烯烃的不对称氢化中的功效。在大多数情况下,阴离子衍生化实际上对铱络合物的不对称诱导没有影响。这与X射线结构研究一致,该研究表明,阳离子金属中心的手性环境不受阴离子取代基的影响。