Direct Asymmetric Aldol Reactions in Water Catalysed by a Highly Active
<i>C</i>
<sub>2</sub>
‐Symmetrical Bisprolinamide Organocatalyst
作者:Joshua P. Delaney、Luke C. Henderson
DOI:10.1002/adsc.201100667
日期:2012.1
A novel C2‐symmetrical bisprolinamide organocatalyst was synthesised and used to facilitate asymmetric direct aldol reactions in a water emulsion. Reactions were performed at room temperature with very low catalyst loadings (1–2.5 mol%) without the required use of additives, co‐catalysts or extended reaction times (24 h). This catalyst system was then used with a variety of aldehyde substrates showing
合成了一种新型的C 2-对称双脯氨酰胺有机催化剂,并用于促进水乳液中的不对称直接羟醛反应。反应是在室温下以极低的催化剂负载量(1-2.5%摩尔)进行的,无需使用添加剂,助催化剂或延长反应时间(24小时)。然后,该催化剂体系与各种醛底物一起使用,显示出对苯甲醛与环己酮的良好反应通用性(dr范围为77/23至> 99/1,抗/ syn;ee范围为33%至> 99%)和中等范围的环戊酮(dr范围45/55至76/24,反/同步;ee范围从14%到68%)。还研究了超低催化剂负载量(0.1和0.05 mol%),表明催化剂的周转量约为1000。