The gas phase 1,2-Wittig rearrangement is an anion reaction. A joint experimental and theoretical study
作者:John C. Sheldon、Mark S. Taylor、John H. Bowie、Suresh Dua、C. S. Brian Chia、Peter C. H. Eichinger
DOI:10.1039/a805319g
日期:——
systems –CH2OMe→ EtO–, and –CH2OEt→PrO–. Each of these exothermic reactions involves migration of an alkyl anion. There are no discrete intermediates in the reaction pathways. There is no indication of a radical pathway for either rearrangement. It is proposed that the gas phase 1,2-Wittig rearrangement involves an anionic migration, and that it is not the barrier to the early saddle point but the Arrhenius
气相1,2-Wittig重排中烷基的迁移倾向已通过以下实验确定。阴离子Ph– – C(OR 1)(OR 2)在碰撞激活时竞争性地重排为两个1,2-Wittig离子PhC(R 1)(OR 2)(O –)和PhC(R 2)( OR 1)(O –)[R 1和R 2 =烷基,R 1 异-Pr>的Et> Me)的:通常用来表明自由基反应的趋势。但是,Hammett对R–C 6 H 4 – – C(OMe)2中MeOH的相对损失的研究表明,随着R的吸电子量增加,该损失显着降低,这一发现与自由基反应不符。从头算起[在CISD / 6-311 ++ G ** // RHF(和UHF)/ 6-311 ++ G **理论水平上)已用于构建模型1,2的潜在表面图-Wittig系统– CH 2 OMe→EtO –和– CH2 OEt→PrO –。这些放热反应的每一个都涉及烷基阴离子的迁移。反应途径中没有离散