Chiral Aldehyde Catalysis for the Catalytic Asymmetric Activation of Glycine Esters
Chiral Aldehyde Catalysis for the Catalytic Asymmetric Activation of Glycine Esters
复制标题
手性醛催化甘氨酸酯的催化不对称活化
DOI：
10.1021/jacs.8b06676
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发表时间：
2018-08-01
影响因子：
15
通讯作者：
Guo, Qi-Xiang
中科院分区：
文献类型：
--
作者：
Wen, Wei;Chen, Lei;Guo, Qi-Xiang
手性醛催化是唯一适合于N-未保护的氨基酸的直接不对称α-官能化，因为醛可以可逆地形成亚胺。然而，很少有关于这些转变的成功报告。事实上，只有手性醛催化的氨基酸的羟醛缩合反应和2-氨基丙二酸酯的烷基化反应具有良好的手性诱导。在这里，我们报告了一种新型的手性醛催化剂的烯醇化中间体的基础上的面控制。所得的手性醛是第一个有效的非吡哆醛依赖性催化剂，可以促进N-未保护的甘氨酸酯的直接不对称α-官能化。通过密度泛函理论计算研究了可能的过渡态和质子转移过程。
Chiral aldehyde catalysis is uniquely suitable for the direct asymmetric alpha-functionalization of N-unprotected amino acids, because aldehydes can reversibly form imines. However, there have been few successful reports of these transformations. In fact, only chiral aldehyde catalyzed aldol reactions of amino acids and alkylation of 2-amino malonates have been reported with good chiral induction. Here, we report a novel type of chiral aldehyde catalyst based on face control of the enolate intermediates. The resulting chiral aldehyde is the first efficient nonpyridoxal-dependent catalyst that can promote the direct asymmetric alpha-functionalization of N-unprotected glycine esters. Possible transition states and the proton transfer process were investigated by density functional theory calculations.