Rate Constants for the β-Elimination of Tosyl Radical from a Variety of Substituted Carbon-Centered Radicals
作者:Vitaliy I. Timokhin、Stéphane Gastaldi、Michèle P. Bertrand、Chryssostomos Chatgilialoglu
DOI:10.1021/jo026870b
日期:2003.5.1
The rate constants for the beta-elimination of tosyl radical (Ts*) from a series of carbon-centered radicals have been determined by using the radical clock methodology. Depending on the substituents R in Ts-CH(2)-CH*R radicals, the rate constants at 293 K vary by more than 2 orders of magnitude in the range of 10(3)-10(6) s(-1). The lowest values were found for the 2-naphthyl and carbamoyl substituents
使用自由基时钟方法已确定了从一系列以碳为中心的自由基中去除甲苯磺酰基自由基(Ts *)的速率常数。取决于Ts-CH(2)-CH * R基团中的取代基R,在293 K处的速率常数在10(3)-10(6)s(-1)范围内变化超过2个数量级。 。发现2-萘基和氨基甲酰基取代基的最小值最低,而苄基取代基位于另一个末端。取代基对起始自由基的稳定化作用在该反应中对降低断裂速率起主要作用。