Accelerating Effect Induced by the Structure of α-Amino Acid in the Copper-Catalyzed Coupling Reaction of Aryl Halides with α-Amino Acids. Synthesis of Benzolactam-V8
作者:Dawei Ma、Yongda Zhang、Jiangchao Yao、Shihui Wu、Fenggang Tao
DOI:10.1021/ja981662f
日期:1998.12.1
hydrophilic groups. No racemization was observed in most cases of this coupling reaction. After some controlled experiments, a possible mechanism including the π-complex and the intramolecular substitution reaction is proposed. Based on this catalyzed reaction, a facile and stereoselective synthesis of benzolactam-V8, a new PKC activator, is achieved.
光学纯的 α-氨基酸与芳基卤化物的偶联产生对映纯的 N-芳基-α-氨基酸,在 CuI 的催化下保留构型。即使对于富电子的芳基卤化物,该反应也可以在比典型的 Ullmann 缩合低得多的温度下完成,这表明该反应中存在由 α-氨基酸结构诱导的加速效应。具有较大疏水基团的α-氨基酸产生较高的偶联产率,而具有较小疏水基团的α-氨基酸仅产生较低的产率,并且对于具有亲水基团的那些没有检测到偶联产物。在该偶联反应的大多数情况下未观察到外消旋化。经过一些对照实验,提出了一种可能的机制,包括 π 络合物和分子内取代反应。