Electro-organic reactions. Part IX. Mechanism of the Kolbe reaction; stereochemistry of reaction of anodically generated cyclohexyl radicals and cations
作者:Geoffrey E. Hawkes、James H. P. Utley、George B. Yates
DOI:10.1039/p29760001709
日期:——
expected proportions. This is compelling evidence that cyclohexyl radicals are not strongly adsorbed at the anode. The stereoisomeric dimers from cis-2-phenylcyclo-hexylcarboxylate are formed in non-random proportions, which supports the view that substitution by aromatic species encourages adsorption. Further oxidation to cyclohexyl cations is also encouraged by 2- and 4-phenyl substitution, and comparison
在甲醇中的可比条件下,已经鉴定和鉴定了一系列4-取代的环己烷羧酸酯(取代基顺式和反式叔丁基和反式苯基)和顺式-2-苯基环己烷羧酸酯的阳极氧化产物。由4-顺-和-反-叔丁基-和-反-苯基化合物以及顺-和反式的立体异构体双环己基(单电子氧化)以统计学上预期的比例形成-1-甲基-4-叔丁基环己烷(与乙酸酯的交叉偶联反应)。这是令人信服的证据,表明环己基自由基没有在阳极上强烈吸附。顺式-2-苯基环己基羧酸酯的立体异构体二聚体以非无规比例形成,这支持了以下观点:被芳香族物质取代会促进吸附。2-和4-苯基取代还鼓励进一步氧化成环己基阳离子,并且与溶剂分解实验的结果比较表明这也是表面效应。