A diastereo- and enantioselective synthesis of α-substituted syn-α,β-diamino acids
A diastereo- and enantioselective synthesis of α-substituted syn-α,β-diamino acids
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DOI：
10.1021/ja8011808
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发表时间：
2008-05-07
影响因子：
15
通讯作者：
Johnston, Jeffrey N.
中科院分区：
文献类型：
--
作者：
Singh, Anand;Johnston, Jeffrey N.
已经开发了取代的α-硝基酯与亚胺的高度非对映选择性和对映选择性加成。高的非对映选择性依赖于以下发现：手性质子催化剂2b和带有2，6-二取代基的α-硝基芳基酯的组合联合收割机组合以将底物控制的非对映选择性提高至>20：1，有利于顺式非对映异构体。此外，手性催化剂通过控制其中甲亚胺π-面被区分的加成步骤提供了99%水平的对映选择性。双功能手性质子酸催化剂使得这些反应能够在没有单独预活化任一底物的情况下进行，从而导致用于形成α，β-二氨基苯基丙氨酸衍生物的直接合成方案。
Highly diastereo- and enantioselective additions of substituted alpha-nitroesters to imines have been developed. High diastereoselection relies on the finding that the combination of chiral proton catalyst 2b and alpha-nitro aryl esters bearing 2,6-disubstitution combine to raise substrate-controlled diastereoselection to >20:1 in favor of the syn diastereomer. Furthermore, the chiral catalyst provides enantioselection to the 99% level through control of the addition step in which the azomethine pi-faces are differentiated. The bifunctional chiral protic acid catalyst enables these reactions to proceed without separate preactivation of either substrate, leading to a straightforward synthetic protocol for the formation of alpha,beta-diamino phenyl alanine derivatives.