Synthesis of Chiral Nitroxides and an Unusual Racemization Reaction.
Synthesis of Chiral Nitroxides and an Unusual Racemization Reaction.
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DOI：
10.1021/jo9808831
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发表时间：
1998-08
期刊：
影响因子：
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通讯作者：
S. Rychnovsky;T. Beauchamp;R. Vaidyanathan;Tricia A. Kwan
中科院分区：
文献类型：
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作者：
S. Rychnovsky;T. Beauchamp;R. Vaidyanathan;Tricia A. Kwan
本文将Lai等人的氮氧自由基的合成方法推广到几种新的手性哌嗪和吗啉氮氧自由基的合成。该策略利用Bargellini反应作为键形成的关键步骤。几个光学纯的氮氧化物纳入α-芳香族和α-螺环中心，通过这条路线制备。这些手性氮氧自由基作为对映选择性氧化剂，作为前手性自由基的捕获剂，以及在新材料的制备中具有重要的应用价值。发现这些氮氧化合物之一，化合物43，在温和的氧化条件下外消旋化。对这一不寻常的外消旋反应的机理进行了探讨。
Lai's protocol for the synthesis of nitroxides has been extended to the synthesis of several new chiral piperazine and morpholine nitroxides. This strategy utilizes the Bargellini reaction as the key bond-forming step. Several optically pure nitroxides incorporating alpha-aromatic and alpha-spiro centers were prepared by this route. These chiral nitroxides will be of interest as enantioselective oxidants, as traps for prochiral radicals, and in the preparation of new materials. One of these nitroxides, compound 43, was found to racemize under mild oxidizing conditions. The mechanism for this unusual racemization reaction was investigated.