Intermolecular N–H Oxidative Addition of Ammonia, Alkylamines, and Arylamines to a Planar σ<sup>3</sup>-Phosphorus Compound via an Entropy-Controlled Electrophilic Mechanism
作者:Sean M. McCarthy、Yi-Chun Lin、Deepa Devarajan、Ji Woong Chang、Hemant P. Yennawar、Robert M. Rioux、Daniel H. Ess、Alexander T. Radosevich
DOI:10.1021/ja412469e
日期:2014.3.26
Ammonia, alkyl amines, and aryl amines are found to undergo rapid intermolecular N-H oxidative addition to a planar mononuclear σ(3)-phosphorus compound (1). The pentacoordinate phosphorane products (1·[H][NHR]) are structurally robust, permitting full characterization by multinuclear NMR spectroscopy and single-crystal X-ray diffraction. Isothermal titration calorimetry was employed to quantify the
发现氨、烷基胺和芳胺会发生快速的分子间 NH 氧化加成到平面单核 σ(3)-磷化合物 (1)。五配位正膦产物 (1·[H][NHR]) 结构坚固,可以通过多核 NMR 光谱和单晶 X 射线衍射进行全面表征。采用等温滴定量热法来量化正丙胺与 1 ((n)PrNH2 + 1 → 1·[H][NH(n)Pr] 的 NH 氧化加成的焓,ΔHrxn(298) = -10.6 kcal/摩尔)。正丙胺 NH 氧化加成的动力学由原位紫外吸收光谱和速率法测定显示出异常大的分子度 (ν = k[1][(n)PrNH2](3))。在 10-70 °C 的温度范围内进行的动力学实验表明,反应速率随着温度的升高而降低。从 Eyring 分析中提取的活化参数 (ΔH(⧧) = -0.8 ± 0.4 kcal/mol, ΔS(⧧) = -72 ± 2 cal/(mol·K)) 表明强 NH 键被 1 裂解为熵由于高度