Electrophilic aromatic substitution. Part VI. Protodesilylation and protodetritiation of some oxygen- and sulphur-containing aromatic compounds and of diphenylmethane. Evidence for hyperconjugation
作者:F. P. Bailey、R. Taylor
DOI:10.1039/j29710001446
日期:——
constituting impressive evidence for hyperconjugation in the latter compounds. The ortho:para ratio decreases along the series CH2Y, OY, SY, (where Y = H, Me, or Ph) and ZMe, ZH, ZPh (where Z = CH2, O, or S) apparently through the increasing importance of the inductive effect at the ortho-position; the previously observed low reactivity of the 2-position of diphenyl sulphide in protodesilylation is confirmed
在50°C下,甲醇-高氯酸中某些芳香族化合物Me 3 Si·C 6 H 4 X的去甲硅烷基化的部分速率因子确定为:(X =)2-OH,3720; 2-SH,4·42;4-SH,11·3;2-SMe,18·4;4-SMe,65·2;2-CH 2 Ph,3·75,并用于在70°C,21,500下破坏三氟乙酸中硫代苯甲醚的2位。硫代苯甲醚和苯硫酚的相对反应性是诱导性的,即与氧和碳类似物的结果相反,SMe的活化度比SH高,这被解释为后者化合物超共轭的令人印象深刻的证据。的邻位:对位比沿系列CH减小2Y,OY,SY(其中Y = H,Me或Ph)和ZMe,ZH,ZPh(其中Z = CH 2,O或S)显然是由于在邻位感应效应的重要性不断提高。先前观察到的原苯甲酸酯化中二苯硫醚2位低反应性得到了证实,并且显示不是异常的。