O,O-二烷基硫代磷(膦)酸酯与三氯氧磷的异构化/氯化反应机理初探

Preliminary Research on Mechanism of the Isomerization/Chlorination of O, O-Dialkylthiophosphate (-onate)with Phosphorus Oxychloride

O，O－二烷基硫代磷（膦）酸酯（1）与三氯氧磷作用得到S-烷基硫代磷酰氯（2）和O-烷基磷酰二氯（3），此反应包含异构化和氧化两个过程．实验结果表明，1的预期氯化产物O-烷基硫代磷（膦）酰氯酯（5）与三氯氧磷不发生反应，而1的预期异构化产物O，S-二烷基硫代磷（膦）酸酯（6）与三氯氧磷能顺利反应得到2．由此推测，在1的异构化／氯化反应中，异构化很可能发生在氯化之前．根据此结果和三角双锥中间体（TBP）概念，提出了该反应初步的可能机理．

In the previous papers, we reported that O,O-dialkylthiophosphate(-onate) 1 reacted with phosphorus oxychloride to give S-alkyl thiophosphoro (-on-)chloridate 2 and Oalkyl phosphorodichloridate 3. Obviously both of isomerization and chlorination occurred in this reaction. The recent experimental results show that phosphorus oxychloride doesn' t react with O-alkyl thiophosphoro(-no)chlorldate 5 which is a desired chlorination product of 1,while it can smoothly react with O,S-dialkythiophosphate(-onate) 6 which is a desired isomerization product of 1 to give 2- Based on this fact we suggest that the isomerization may occur ahead of the chlorination in the isomerization/chlorination of 1. In the light of the above results and trigonal bipyramid (TBP) intermediate concept, the mechanism 0f the isomerization /chlorination of 1 is discussed.