The Asymmetric Dialkylzinc Addition to Imines Catalyzed by [2.2]Paracyclophane-Based <i>N</i>,<i>O</i>-Ligands
作者:Stefan Dahmen、Stefan Bräse
DOI:10.1021/ja025831e
日期:2002.5.1
enantioselective dialkylzincaddition to imines in the presence of catalytic amounts of N,O-ligands is reported. N-formyl-alpha-(p-tolysulfonyl)benzylamines are the readily available starting materials easily obtained in a one-pot synthesis from benzaldehydes, formamide, and p-tolylsulfinic acid. Upon deprotonation, the sulfinate is eliminated to give the acyl imine. The acyl imines further react with
据报道,在催化量的 N,O-配体存在下,首次对亚胺具有高度对映选择性的二烷基锌加成。N-甲酰基-α-(对甲苯磺酰基)苄胺是容易获得的起始原料,可通过苯甲醛、甲酰胺和对甲苯基亚磺酸一锅法合成。去质子化后,亚磺酸盐被消除,得到酰基亚胺。在催化量的基于 [2.2] 对环芳烷的 N,O-配体 L 的存在下,酰基亚胺进一步与烷基锌试剂反应,产生具有优异产率和对映选择性的烷基化 N-(1-苯丙基)甲酰胺。
Discovery of chiral catalysts by asymmetric activation for highly enantioselective diethylzinc addition to imines: using racemic and achiral diimines as effective activators
作者:Hua Liu、Hai-Le Zhang、Shuang-Jun Wang、Ai-Qiao Mi、Yao-Zhong Jiang、Liu-Zhu Gong
DOI:10.1016/j.tetasy.2005.07.014
日期:2005.9
A library of chiral zinc complexes formed in Situ by the combination of achiral and racemic diimines with 3,3'-di(3,5-ditrifluoromethylphenyl)-BINOL and diethylzinc were evaluated in the asymmetric addition of diethylzine to N-acylimines. In the presence of 10 mol % of chiral ligand 4 and racemic diimine 5, high enantioselectivities of up to 97% ee and yields of up to 96% were achieved for a wide range of aromatic imines in dichloromethane at -30 degrees C. (c) 2005 Elsevier Ltd. All rights reserved.
Asymmetric, Catalytic Phenyl Transfer to Imines: Highly Enantioselective Synthesis of Diarylmethylamines
Paracyclophanes in Action: Asymmetric Catalytic Dialkylzinc Addition to Imines Using [2.2]Paracyclophane-based N,O-Ligands as Catalysts
作者:Stefan Dahmen、Stefan Bräse
DOI:10.1002/ijch.201100078
日期:2012.2
The asymmetricaddition of dibutylzinc to imines is achieved by employing [2.2]paracyclophane‐based ketimine ligands with good to excellent enantioselectivities. A comparison to other organozinc reagent is made.