An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to nitroalkenes has been developed. This reaction afforded the chiral pyrazol-3-ol derivatives in high to excellent yields (up to >99%) with high enantioselectivities (up to 94% ee) for most substrates under very low catalyst loading (0.25 mol%). This catalytic asymmetric reaction provides valuable and easy access to chiral pyrazol-3-ol derivatives, which possess potential pharmaceutical activity.
开发了一种高效的手性四
羧酸酰胺催化的对硝基烯烃的对映选择性迈克尔加成反应,使用的是
吡唑啉-5-酮。该反应在极低的催化剂用量(0.25摩尔%)下,对大多数底物获得了高至优异的产率(最高可达>99%)和高对映选择性(最高可达94%的ee),得到了手性
吡唑-3-醇衍
生物。该催化不对称反应为获得具有潜在药理活性的手性
吡唑-3-醇衍
生物提供了宝贵而简便的途径。