An organophosphane catalyst derived from L-proline was shown to be a very effective catalyst for asymmetric Michael addition reactions of various chalcones to cyclic ketones including both cyclohexanone and cyclopentanone. The corresponding adducts could be obtained in high yields (up to 91 %) and with excellent enantioselectivities (up to 99 % ee) and diastereomeric ratios (up to >99:1). A possible
来自
L-脯氨酸的有机膦催化剂被证明是一种非常有效的催化剂,用于各种
查耳酮与环酮(包括
环己酮和
环戊酮)的不对称迈克尔加成反应。相应的加合物可以以高产率(高达 91%)和出色的对映选择性(高达 99%ee)和非对映体比率(高达 >99:1)获得。已经提出了基于 31 P NMR 和 ESI-MS 观察的可能的催化机制,用于这种有机膦催化的迈克尔加成。