我们在这里报告了醛之间的催化不对称迭代和多米诺交叉羟醛反应,具有高度的稳健性、灵活性和通用性。Cu(I)-DTBM-SEGPHOS 复合物催化受体醛和由供体醛衍生的硼烯醇化物之间的不对称交叉羟醛反应,该反应是通过 Ir 催化的烯丙氧基硼酸酯异构化产生的。可以重复使用醛醇产物作为随后不对称醛醇反应的受体底物的单元过程。双醇醛反应的供体醛和立体选择性可以以逐步的方式灵活切换。此外,使用适量的供体和胺添加剂,可以在一锅法中进行不对称的三重和四重醛醇反应,通过控制多达八个立体中心快速拉长碳骨架。该方法可用于直接合成对映异构和非对映异构富集的 1,3-多元醇。
Histidine-Catalyzed Asymmetric Aldol Addition of Enolizable Aldehydes: Insights into its Mechanism
作者:Ulf Scheffler、Rainer Mahrwald
DOI:10.1021/jo202558f
日期:2012.3.2
Extensive studies of asymmetric cross-aldol addition between enolizablealdehydes are described and provide a deeper insight into histidine-catalyzed aldol additions. In particular, aspects of enantio- as well as diastereoselectivity of these reactions are discussed. Rules and predictions of configurative outcome are explained by using different transition-state models. These discussions are confirmed
Asymmetric Histidine-Catalyzed Cross-Aldol Reactions of Enolizable Aldehydes: Access to Defined Configured Quaternary Stereogenic Centers
作者:Morris Markert、Ulf Scheffler、Rainer Mahrwald
DOI:10.1021/ja907054y
日期:2009.11.25
A histidine-catalyzed asymmetric direct cross-aldol reaction of enolizable aldehydes is described. In contrast to proline, histidine is able to clearly differentiate the reactivity of various aldehydes. In addition, this approach provides access to syn-configured B-hydroxyaldehydes. Thus, by application of this new methodology, defined-configuration quaternary stereocenters can be constructed with ease. The utility of this method is demonstrated in several total syntheses of branched-chain carbohydrates.