Supported l-proline on zirconium phosphates methyl and/or phenyl phosphonates as heterogeneous organocatalysts for direct asymmetric aldol addition
作者:Salvatore Calogero、Daniela Lanari、Mara Orrù、Oriana Piermatti、Ferdinando Pizzo、Luigi Vaccaro
DOI:10.1016/j.jcat.2011.06.004
日期:2011.8
Zirconium phosphates methyl and/or phenyl phosphonates-supported l-proline have been prepared as amorphous solids by precipitation of (4R)-4-(phosphonooxy)-l-proline, methyl and/or phenyl phosphonic acid with ZrOCl2. The supported l-proline catalysts were tested on the direct asymmetric aldol addition of cyclohexanone to p-nitrobenzaldehyde in DMF/H2O (9:1) and in sole water. The hydrophobic groups
通过用ZrOCl 2沉淀(4 R)-4-(膦酰氧基)-1-脯氨酸,甲基和/或苯基膦酸,已将磷酸锆甲基和/或苯基膦酸酯负载的1-脯氨酸制备为无定形固体。在DMF / H 2 O(9:1)和单一水中,将环己酮直接不对称羟醛直接加到对硝基苯甲醛中,对负载的1-脯氨酸催化剂进行了测试。固体表面上的疏水基团有利于试剂向脯氨酸手性部分的扩散,从而增加了负载的1-脯氨酸的催化活性。高非对映选择性(反/同步) 高达94:6)和高对映体过量高达97%。