Substituent effects on the rate of carbene formation by the pyrolysis of rigid aryl substituted diazomethanes
作者:Naresh C Mathur、Miles S Snow、Kent M Young、James A Pincock
DOI:10.1016/s0040-4020(01)96390-2
日期:1985.1
Rate constants for the pyrolysis of 1-diazo-4,4-dimethyl-1,4-dihydronaphthalenes, 4a–4e, have been measured in methanol : 6% triethylamine. In contrast to non-rigid cases, like diphenyldiazomethanes, where all para substituents show a rate increase compared to hydrogen, these rates show a linear Hammett correlation for para substituents with σ+ = — 0.84. This observation is rationalized by a non-linear
1-重氮-4,4-二甲基-1,4-二氢萘(4a-4e)的热解速率常数已在甲醇:6%三乙胺中测定。与非刚性情况(如二苯基重氮甲烷)相反,在该情况下,所有对位取代基均比氢显示出速率增加,这些速率显示出对位取代基的线性Hammett相关性,其中σ + =-0.84。通过非线性过程合理化该观察结果,该过程涉及直接导致卡宾基态单峰态的氮的流失17。然后将该卡宾捕集,得到醚11。