Well-Defined Chiral Spiro Iridium/Phosphine−Oxazoline Cationic Complexes for Highly Enantioselective Hydrogenation of Imines at Ambient Pressure
作者:Shou-Fei Zhu、Jian-Bo Xie、Yong-Zhen Zhang、Shen Li、Qi-Lin Zhou
DOI:10.1021/ja063444p
日期:2006.10.1
catalyze the hydrogenation of acyclic N-aryl ketimines under ambient pressure with excellent enantioselectivities (up to 97% ee) and full conversions. This result represents the highest enantioselectivity and the first example of the hydrogenation of imines catalyzed by chiral analogues of the Crabtree catalyst at ambient pressure. Studies on the stability of the catalysts revealed that the catalysts Ir-SIPHOX
从光学纯的 7-diphenylphosphino-7'-trifluoromethanesulfonyloxyl-1,1'-spirobindane 开始,分四步合成了具有刚性和庞大螺二茚烷支架的新型手性膦-恶唑啉配体(7,SIPHOX),总含量为 40-64%屈服。铱配合物 7,Crabtree 催化剂的手性类似物,是通过配体 7 和 [Ir(COD)Cl](2) 在 tetrakis-3,5-bis(trifluoromethyl)phenylborate 钠存在下的配位生成的。通过NMR、ESI-MS和X-射线衍射分析表征配合物。Ir-SIPHOX 配合物可以在环境压力下催化无环 N-芳基酮亚胺的氢化,具有出色的对映选择性(高达 97% ee)和完全转化。该结果代表了最高的对映选择性和在环境压力下由 Crabtree 催化剂的手性类似物催化的亚胺氢化的第一个例子。对催化剂稳定性的研究表明,Ir-SIPHOX