在这里,我们报告了膦酸单酯化和二酯化的直接和选择性合成程序。研究了一系列烷氧基供体,发现原乙酸三乙酯是进行转化的最佳试剂和溶剂。发现了对反应过程的重要温度影响。取决于反应温度,以合适的产率专门获得膦酸的单乙酯或二乙酯。所提出的方法的底物范围在芳香族和脂肪族膦酸上得到验证。所设计的方法可成功应用于小规模和大规模实验,而不会显着降低选择性或反应收率。进行了几次专门的实验以深入了解反应机理。在 30 °C 时,单酯通过中间体(膦酸的 1,1-二乙氧基乙酯)形成。在更高的温度下,类似的中间体形式产生二酯或稳定且可检测的焦膦酸盐,它们也被消耗以产生二酯。31 P NMR 光谱用于确定焦膦酸酯的结构并监测反应过程。不需要额外的试剂、良好的可及性和直接的纯化是所开发协议的重要方面。
The Chemistry of Phosphapeptides: Formation of Functionalized Phosphonochloridates under Mild Conditions and Their Reaction with Alcohols and Amines
作者:William P. Malachowski、James K. Coward
DOI:10.1021/jo00104a016
日期:1994.12
A variety of methods have been explored for the convergent synthesis of phosphonamidates and phosphonates via phosphonochloridates. In the absence of complex functionality, phosphorus pentachloride is an effective reagent for the conversion of diethyl and diisopropyl phosphonates to phosphonochloridates. Subsequent reaction with amines and alcohols provides good yields of the phosphonamidates and mixed phosphonates, respectively. However, in the presence of more complex functionality, a milder method utilizing oxalyl chloride to generate the phosphonochloridate from a monomethyl phosphonic acid is required. Aminolysis of the dimethyl phosphonates generates the requisite monomethyl phosphonic acids which are cleanly converted to phosphonochloridates and reacted with amines and primary alcohols.
proposed methodology was verified on aromatic as well as aliphatic phosphonic acids. The designed method can be successfully applied for small- and large-scale experiments without significant loss of selectivity or reaction yield. Several devoted experiments were performed to give insight into the reaction mechanism. At 30 °C, monoesters are formed via an intermediate (1,1-diethoxyethyl ester of phosphonic
在这里,我们报告了膦酸单酯化和二酯化的直接和选择性合成程序。研究了一系列烷氧基供体,发现原乙酸三乙酯是进行转化的最佳试剂和溶剂。发现了对反应过程的重要温度影响。取决于反应温度,以合适的产率专门获得膦酸的单乙酯或二乙酯。所提出的方法的底物范围在芳香族和脂肪族膦酸上得到验证。所设计的方法可成功应用于小规模和大规模实验,而不会显着降低选择性或反应收率。进行了几次专门的实验以深入了解反应机理。在 30 °C 时,单酯通过中间体(膦酸的 1,1-二乙氧基乙酯)形成。在更高的温度下,类似的中间体形式产生二酯或稳定且可检测的焦膦酸盐,它们也被消耗以产生二酯。31 P NMR 光谱用于确定焦膦酸酯的结构并监测反应过程。不需要额外的试剂、良好的可及性和直接的纯化是所开发协议的重要方面。