18709-33-6Relevant academic research and scientific papers
1,3-benzyl migration in iminium ions: Evidence for a fast free-radical chain reaction
Blank, Nancy,Straub, Bernd F.,Opatz, Till
experimental part, p. 7355 - 7365 (2012/01/06)
The "exocyclic" 1,3-benzyl shift observed in iminium salts derived from 1-benzyl-1,2,3,4-tetrahydroisoquinolines is related to the "endocyclic" Knabe rearrangement. A crossover experiment, isotopic labelling, the study of initiators and inhibitors as well as DFT calculations of gas-phase model structures provide evidence for a free-radical pathway under kinetic entropy control that is not affected by "slow" radical traps. An unexpected rearrangement of methyleneiminium ions derived from 1-benzyl-1,2,3,4-tetrahydroisoquinolines has been investigated by isotopic labelling, trapping experiments and DFT calculations. Theobserved benzyl migration proceeds by an exceptionally fast radical chain reaction closely related to the Knabe reaction.Remarkably, the process is inhibited byneither methyl acrylate nor dioxygen. Copyright
