Asymmetric synthesis of acyclic amines through Zr- and Hf-catalyzed enantioselective alkylzinc reagents to Imines
Asymmetric synthesis of acyclic amines through Zr- and Hf-catalyzed enantioselective alkylzinc reagents to Imines
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DOI：
10.1002/adsc.200404319
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发表时间：
2005-02-01
影响因子：
5.4
通讯作者：
Hoveyda, AH
中科院分区：
文献类型：
--
作者：
Akullian, LC;Porter, JR;Hoveyda, AH
容易获得的手性氨基酸基配体用于烷基锌试剂与各种芳族和脂族亚胺的金属催化加成;有效地形成所需的胺产物，并具有高水平的光学纯度。在更多的刘易斯酸性Zr盐提供较低效率的情况下，Hf基催化剂提供显著更高的产率和相似的对映选择性。讨论了N-活化基团的关键结构特征以及最佳手性配体。一个机械的工作模型，合理化现有的数据，并作为一个预测工具。
Readily available chiral amino acid-based ligands are used in metal-catalyzed additions of alkyl-zinc reagents to various aromatic and aliphatic imines; the desired amine products are formed efficiently and in high levels of optical purity. In cases where the more Lewis acidic Zr salts afford lower efficiency, Hf-based catalysts deliver significantly higher yields with similar enantioselectivities. Critical structural features of the N-activating groups as well as the optimal chiral ligands are discussed. A mechanistic working model is presented to rationalize the existing data and to serve as a predictive tool.