顺[1-溴-2-羟基-2-(对-甲氧基苯基)乙基]膦酸二异丙酯的羟基反应性能的研究

研究了顺1-溴-2-羟基-2-(对-甲氧基苯基)乙基]膦酸二异丙酯羟基的反应性能。由于膦酸酯基和电负性的溴原子的吸电子作用，羟基氧原子周围的电子云密度降低．从而增强了羟基上质子的酸性并减弱了碱性条件下相应的烷氧基负离子的亲核能力，因而得到了有关羟基与酚进行Mitsunobu脱水反应和酯化反应的特殊反应性能。同时，由于氢键的作用和膦酸酯基团的空问障碍作用，羟基与酰氯的反应活性较低。

Study on the Reactivity of Hydroxyl Group of the syn Diisopropyl 1-Bromo-2-hydroxy-2-(p-methoxyphenyl)ethylphosphonate

The reactivity of the hydroxyl group of the syn diisopropyl 1-bromo-2-hydroxy-2-(p-methoxyphenyl)ethylphosphonate was studied. Due to the electron-withdrawing effects from both the phosphonate group and the electronegative bromine atom, the electron density around the oxygen atom of the hydroxyl group was lowered, which resulted in the acidity increase of the hydroxyl proton and nucleophilicity decrease of the corresponding alkoxide anion under basic conditions. Therefore, unusual reactivity dealing with Mitsunobu dehydation reaction and esterification were found. And also, the steric hindrance arisen from the formation of hydrogen bond and the bulky phosphonate group should partly account for the poor reactivity of the hydroxyl group with acyl chlorides.