Asymmetric hydrogenation of N-alkyl and N-aryl ketimines using chiral cationic Ru(diamine) complexes as catalysts: the counteranion and solvent effects, and substrate scope
作者:Fei Chen、Ziyuan Ding、Yanmei He、Jie Qin、Tianli Wang、Qing-Hua Fan
DOI:10.1016/j.tet.2012.03.019
日期:2012.7
Asymmetric hydrogenation of N-alkyl and N-aryl ketimines catalyzed by chiral cationic η6-arene-(N-monosulfonylated diamine) Ru(II) complexes has been investigated. Strong counteranion and solvent effects on the enantioselectivity were observed. The ruthenium catalyst bearing non-coordinating BArF− anion was found to be particularly effective for the hydrogenation of acyclic and exocyclic N-alkyl ketimines
的不对称氢化ñ -烷基和Ñ通过催化芳基酮亚胺的手性阳离子η 6 -arene-(Ñ -monosulfonylated二胺)的Ru(II)络合物进行了研究。观察到强烈的抗衡阴离子和溶剂对对映选择性的影响。钌催化剂轴承非配位BARF -阴离子被认为是对无环和环外的氢化特别有效ñ -烷基酮亚胺在(BOC)的存在下2O在二氯甲烷中或什至在无溶剂条件下提供的手性胺,其ee可达99%以上,并具有完全转化率。或者,在不存在(Boc)2 O的情况下,具有手性磷酸根阴离子和相应磷酸作为添加剂的钌催化剂也有效用于N-烷基酮亚胺的氢化,对映选择性和完全转化率优异。对于Ñ -芳基酮亚胺降低通过使用钌催化剂轴承BARF观察对映体过量-阴离子。因此,该催化方案为光学活性胺提供了简便实用的途径,并已成功用于对映体纯的(+)-舍曲林的克级合成中。