homogeneity and high reactivity. The corresponding Michael addition reactions were found to proceed at room temperature in the presence of catalytic amounts of DBU to afford quantitatively the addition products with virtually complete diastereoselectivity. Acidic decomposition of the products followed by treatment of the reaction mixture with NH4OH gave rise to the diastereomerically pure 3-substituted
通过合理设计单首选过渡态,并通过电子供体-受体型吸引相互作用使其稳定,已确定了相应起始化合物的结构和几何要求。甘
氨酸的席夫碱与邻-[N-α-
吡啶甲基
氨基]
苯乙酮(作为亲核甘
氨酸等效物)和N-(反式-烯酰基)
恶唑烷-2-酮(作为α的衍
生物)的Ni(II)配合物,发现β-不饱和
羧酸是具有几何/构象均质性和高反应性的选择底物。发现相应的迈克尔加成反应在室温下在催化量的
DBU存在下进行,以定量提供具有几乎完全非对映选择性的加成产物。