Controlled Reversible Anchoring of η6-Arene/TsDPEN- Ruthenium(II) Complex onto Magnetic Nanoparticles: A New Strategy for Catalyst Separation and Recycling
作者:Lei Wu、Yan-Mei He、Qing-Hua Fan
DOI:10.1002/adsc.201100317
日期:2011.11
A newcatalystseparation and recycling protocol combining magneticnanoparticles and host-guest assembly was developed. The catalyst, (η6-arene)[N-(para-toluenesulfonyl)-1,2-diphenylethylenediamine]ruthenium trifluoromethanesulfonate [Ru(OTf)(TsDPEN)(η6-arene)] bearing a dialkylammonium salt tag, was easily separated from the reaction mixtures by magnet-assisted decantation, on basis of the formation
开发了一种新的催化剂分离和回收方案,该方案结合了磁性纳米颗粒和客体组装。的催化剂,(η 6 -arene)ñ - (对甲苯磺酰)-1,2-二苯基乙二胺]合钌三氟甲磺酸酯的[Ru(OTF)(TsDPEN)(η 6 -arene)]轴承二烷基铵盐标签,被容易地分离二苯并[24]冠-8修饰的Fe 3 O 4形成假轮烷配合物的基础上,通过磁辅助倾析法从反应混合物中分离得到纳米粒子。钌催化剂已经成功地重复使用了至少5次,同时保留了对映体选择性,但以2-甲基喹啉的不对称氢化中相对较低的催化活性为代价。
An Investigation into the Tether Length and Substitution Pattern of Arene-Substituted Complexes for Asymmetric Transfer Hydrogenation of Ketones
作者:Fung K. Cheung、Changxue Lin、Franco Minissi、Adriana Lorente Crivillé、Mark A. Graham、David J. Fox、Martin Wills
DOI:10.1021/ol702226j
日期:2007.10.1
A series of Ru(II) catalysts were prepared and tested in the asymmetric transfer hydrogenation of ketones. The catalyst containing a "4-carbon" tether gave the fastest rates of ketone reduction. This is due to both increased rate of regeneration of hydride "Ru-H" and increased rate of ketone reduction. Several classes of ketone were reduced in enantiomeric excesses of up to 97%. Substituents on the arene ring of the catalyst influence the reaction rate and enantioselectivity.