Polar Effects in the Reactions of a Series of Substituted Diphenyldiazomethanes with Chloranil
作者:Takumi Oshima、Toshikazu Nagai
DOI:10.1246/bcsj.53.3284
日期:1980.11
contribution of the para substituents. The products of these reactions were the corresponding 2,3,5,6-tetrachlorohydroquinone poly(benzhydryl)ethers, but these polyethers were easily hydrolyzed into the corresponding benzophenones and tetrachlorohydroquinone(HQ). On the other hand, the initial presence of water or methanol as an additive changed the reaction features to give benzophenone or α,α-dimethoxydiphenylmetha
在四氢呋喃中研究了 15 种间位和对位取代的二苯基重氮甲烷与氯苯醌的反应动力学和产物。二级速率常数 k 随取代基的给电子能力而增加,其值可能与 Yukawa-Tsuno 方程相关:logk⁄k0=-1.67(σ0+0.66Δ\barσR+)+0.009, (r=0.996)。ρ 值 -1.67 表明过渡态重氮碳处正电荷的大量发展,而 R 值 0.66 证实了对位取代基的 π 电子贡献使正电荷相当稳定。这些反应的产物是相应的 2,3,5,6-四氯氢醌聚(二苯甲基)醚,但这些聚醚很容易水解成相应的二苯甲酮和四氯氢醌(HQ)。另一方面,作为添加剂的水或甲醇的初始存在改变了反应特征,得到二苯甲酮或 α,α-二甲氧基二苯基甲烷...