Reactions of lead(IV). Part XXVIII. Oxidative coupling of methylsubstituted benzenoid compounds: formation of biaryls and diarylmethanes in trifluoroacetic acid
作者:Richard O. C. Norman、C. Barry Thomas、John S. Willson
DOI:10.1039/p19730000325
日期:——
Methyl-substituted benzenes are oxidised readily at low temperatures by lead tetra-acetate in the presence of trifluoroacetic acid; the products are mainly biaryls and diarylmethanes, in proportions which vary markedly with the structure of the aromatic compound. Evidence has been adduced that the first step is the formation of an aromatic radical cation. This undergoes competitive reactions; it can
甲基取代的苯在三氟乙酸的存在下,在低温下容易被四乙酸铅氧化。产物主要是联芳基和二芳基甲烷,其比例随芳族化合物的结构而显着变化。已经有证据表明第一步是形成芳族自由基阳离子。这经历了竞争反应;它可以与另一个芳族分子反应,最终得到联芳基,在这方面,它表现为亲电子基团而不是阳离子,或者可以进一步氧化生成苄基阳离子,由此衍生出二芳基甲烷。