Simple amphiphilic isosteviol–proline conjugates as chiral catalysts for the direct asymmetric aldol reaction in the presence of water
作者:Ya-Jie An、Yun-Xiao Zhang、Ya Wu、Zhao-Min Liu、Chao Pi、Jing-Chao Tao
DOI:10.1016/j.tetasy.2010.04.019
日期:2010.4
activity (up to >99% yield) and stereoselectivity (up to 99:1 dr, >99% ee) for the direct aldol reaction of cyclohexanone and substituted benzaldehydes at room temperature in the presence of water. In addition, solvent effects, catalyst loading, substrate scope, temperature, and the influence of water on the reactions were investigated. These results demonstrate that the catalysts with a chiral concave
通过一锅法将异osteviol与l-脯氨酸缩合,合成了两种新型的两亲催化剂3和4。在仅1 mol%的负载量下,催化剂3在室温下于室温下对环己酮和取代的苯甲醛的直接羟醛反应显示出优异的活性(高达> 99%的收率)和立体选择性(高达99:1 dr,> 99%ee)。水的存在。此外,还研究了溶剂效应,催化剂负载量,底物范围,温度以及水对反应的影响。这些结果表明,在1-脯氨酸的4-位上具有手性凹和疏水取代基的催化剂为反应提供了高活性和立体选择性。