Amination of phenylketenes. Substituent effect on amine-catalyzed tautomerization of amide enol
作者:Md. Mizanur Rahman Badal、Min Zhang、Shinjiro Kobayashi、Masaaki Mishima
DOI:10.1002/poc.3162
日期:2013.12
reaction of substituted phenylketenes with diethylamine in acetonitrile were suggested to be the amide enols rather than the zwitterions on the basis of the theoretical calculations. A single broad band at 1674 cm−1 observed for reaction with the primary amines was attributed to overlap of two bands of the intermediate (amide enol) and the final product (amide). The substituent effect for the second‐order
根据理论计算,在取代的乙烯酮与二乙胺在乙腈中的反应中观察到的在1676–1680 cm -1处具有红外波段的瞬态中间体被认为是酰胺烯醇而不是两性离子。与伯胺反应观察到的在1674 cm -1的单个宽带归因于中间体(酰胺烯醇)和最终产物(酰胺)的两个谱带的重叠。由汤川-津野方程成功地分析了酰胺烯醇中间体的二乙胺-催化的互变异构化的二阶速率常数,得到酰胺的取代基的效果,给出0.63ρ值和- [R - 1.31值。的[R -苯酚的pK a的值大于1时,表明在过渡状态下酰胺烯醇的氧原子上形成的负电荷通过乙烯基显着离位到芳族π系统中。这[R -值被认为反映β-phenylenolate骨架的内在属性。ρ值非常小,归因于循环过渡结构,其中负电荷分散在六元环中。版权所有©2013 John Wiley&Sons,Ltd.