Acid-catalysed aromatisation of benzene cis-1,2-dihydrodiols: a carbocation transition state poorly stablised by resonance
作者:Derek R. Boyd、John Blacker、Briege Byrne、Howard Dalton、Mark V. Hand、Sandra C. Kelly、Rory A. More O'ferrall、S. Nagaraja Rao、Narain D. Sharma、G. N. Sheldrake
DOI:10.1039/c39940000313
日期:——
Acid-catalysed dehydration of 3-substituted benzene cis-1,2-dihydrodiols exhibits a Hammett plot with ρ=–8.2, consistent with reaction via a benzenonium ion-like intermediate; however, correlation of +M resonance substituents such as Me and MeO by σp rather than σ+ constants indicates a marked imbalance between resonance and inductive stabilisation of the transition state.
酸催化下3-取代苯顺-1,2-二氢二醇的脱水反应呈现出ρ=–8.2的哈米特图,这与通过类似苯镝离子中间体的反应途径一致;然而,通过σp而非σ+常数关联甲基和甲氧基等+M共振取代基,表明过渡态的共振与诱导稳定之间存在明显失衡。