Aminolyses of Aryl Diphenylphosphinates and Diphenylphosphinothioates: Effect of Modification of Electrophilic Center from PO to PS
作者:Ik-Hwan Um、Kalsoom Akhtar、Young-Hee Shin、Jeong-Yoon Han
DOI:10.1021/jo070171n
日期:2007.5.1
small degree of bond fission. Reactions of 2,4-dinitrophenyl diphenylphosphinothioate (2a) with alicyclic secondary amines result in a good linear Brønsted-type plot with βnuc = 0.52, implying that the reactions proceed through a concerted mechanism. The βnuc value determined for the reactions of 2a is slightly larger than that reported for the corresponding reactions of 2,4-dinitrophenyl diphenylphosphinate
动力学研究报道了芳基二苯基硫代磷酸酯(2a - i)的氨解。所述phosphinothioates 2A -我比芳diphenylphosphinates反应性更低(1A -我),的氧类似物2A -我,无论离开芳氧基或攻击胺的碱度。2b - i与哌啶反应的Yukawa-Tsuno图显示了良好的线性,且r值较小(r= 0.28),表明离去基团在速率确定步骤离去,键裂的程度很小。2,4-二硝基苯基二苯基硫代磷酸酯(2a)与脂环族仲胺的反应产生良好的线性布朗斯台德型图,βnuc = 0.52,这表明该反应是通过协同机理进行的。的β NUC值确定的反应图2a比所报道的2,4-二硝基苯基二苯基次膦(相应反应稍大1A,即,β NUC = 0.38),这表明反应的图2a进行通过更紧密的过渡态( TS)大于1a。的反应具有哌啶的图2a显示出约1。0.4千卡/摩尔活化的更有利的焓(Δ ħ ⧧)比的图1A。相反,活化的在25