作者:Athelstan L. J. Beckwith、Graeme Moad
DOI:10.1039/p29800001473
日期:——
Mono- and bi-cyclic radicals containing the cyclopropylmethyl system are readily generated by interaction of the appropriate halides with triphenyl- or tributyl-stannane. Each radical studied underwent ring-opening by fission of the more substituted βγ-bond. In the case of the secondary radical (12b) the new double bond was formed preferentially in the trans-configuration. Rate constants, which cannot
通过适当的卤化物与三苯基或三丁基锡烷的相互作用,容易产生含有环丙基甲基系统的单环和双环基团。每个被研究的基团都通过更取代的βγ键的裂变而开环。在第二自由基(12b)的情况下,优先以反式构型形成新的双键。无法通过此方法高精度确定的速率常数在1×10 7 –3×10 8 s –1的范围内在25°C下。当通过流动方法在esr腔中产生时,α-羟基环丙基甲基自由基经历β裂变,随后进行1,5-氢原子转移以提供烯氧基。与非极性溶剂相比,后者在水中的反应更慢。刚性羟基降三环基自由基(43)可能会由于过渡态的偶极性质而优先发生取代度较低的βγ键的裂变。