l-Proline anchored hydrotalcite clays: An efficient catalyst for asymmetric Michael addition
l-Proline anchored hydrotalcite clays: An efficient catalyst for asymmetric Michael addition
复制标题
DOI：
10.1016/j.apcata.2008.01.030
复制
发表时间：
2008-05
影响因子：
5.5
通讯作者：
Sakthivel Vijaikumar;A. Dhakshinamoorthy;K. Pitchumani
中科院分区：
文献类型：
--
作者：
Sakthivel Vijaikumar;A. Dhakshinamoorthy;K. Pitchumani
L-脯氨酸被固定在水滑石粘土的夹层上。这种L锚定的水滑石在β-硝基苯乙烯与丙酮的不对称Michael加成反应中具有良好的催化活性。与纯L-脯氨酸催化反应相比，不对称诱导反应发生了反转。同样的迈克尔加合物已经通过两种方法得到：第一种是通过丙酮与β-硝基苯乙烯加成(烯胺类加成)，第二种是通过硝基甲烷与亚甲基丙酮加成(亚胺类加成)。这种手性氨基催化剂(HTLP)对烯胺类和亚胺类加成反应都具有较好的催化作用，表明水滑石是L-脯氨酸较好的载体。它在标题反应中也起到了助催化剂的作用。对烯胺和亚胺类加成反应均提出了合适的反应机理。
l-Proline has been immobilized onto the inter layers of hydrotalcite clay. This l-proline-anchored hydrotalcite (HTLP) has good catalytic activity in the asymmetric Michael addition reaction between β-nitrostyrene and acetone. An inversion in the asymmetric induction is observed when compared to the reaction using pure l-proline catalysis. The same Michael adduct has been prepared by two methods: first, by addition of acetone to β-nitrostyrene (an enamine-type addition) and secondly, by addition of nitromethane to benzylideneacetone (an iminium-type addition). This chiral amino catalyst (HTLP) acts as a better catalyst for both enamine-type and iminium-type additions, indicating clearly that hydrotalcite is a better support for l-proline. It also acts as a cocatalyst in the title reaction. Suitable mechanisms are proposed for both enamine- and iminium-type additions.