Generation of chiral phosphonium dialkyl phosphite as a highly reactive P-nucleophile: application to asymmetric hydrophosphonylation of aldehydes.
Generation of chiral phosphonium dialkyl phosphite as a highly reactive P-nucleophile: application to asymmetric hydrophosphonylation of aldehydes.
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DOI：
10.1021/ja810043d
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发表时间：
2009-02
影响因子：
15
通讯作者：
D. Uraguchi;T. Ito;T. Ooi
中科院分区：
文献类型：
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作者：
D. Uraguchi;T. Ito;T. Ooi
通过低温核磁共振分析检测到了手性四氨基膦二烷基亚磷酸酯的生成，并且通过将其应用于建立各种醛的高效和对映选择性氢膦酰化反应，成功证明了其作为具有显着反应活性的P-亲核试剂的合成潜力。对有机碱依赖性所需离子对的生成及其作为 P-亲核试剂的反应性和选择性的系统评估表明，碱的阳离子共轭酸的结构是大量生成具有突出亲核性的亚磷酸根阴离子和严格立体控制的关键元素。这项研究不仅提供了亚磷酸酯互变异构体在 P-C 键形成过程中重要性的实验证明，而且还为高级手性有机碱催化剂的分子设计提供了通用但有价值的框架。
The generation of chiral tetraaminophosphonium dialkyl phosphite has been detected by low-temperature NMR analysis, and its synthetic potential as a remarkably reactive P-nucleophile has been successfully demonstrated by its application to the establishment of highly efficient and enantioselective hydrophosphonylation of various aldehydes. A systematic evaluation of the organic-base-dependent generation of the requisite ion pair and its reactivity and selectivity as a P-nucleophile reveals that the structure of the cationic conjugate acid of the base is a key element both for substantial generation of phosphite anions with prominent nucleophilicity and for rigorous stereocontrol. This study provides not only experimental demonstration of the importance of the phosphite tautomer in the P-C bond formation process but also a general yet valuable framework for the molecular design of even superior chiral organic base catalysts.