Dissociative ionization of aryl-substituted vinyl bromides in the gas phase: experimental and computational evidence for the formation of stable .alpha.-arylvinyl cations both by direct means and by spontaneous exothermic isomerization of unstable isomeric ions
Teilweise Sauerstoff-Wanderung in der photochemischen Wolff-Umlagerung – α-Oxocarben-Oxiren-Isomerisierung oder intermolekularer Mechanismus?
作者:Peter Haiss、Klaus-Peter Zeller
DOI:10.1515/znb-2003-0616
日期:2003.6.1
Crossover experiments between isotopomeric species of 2-diazo-1-oxo-1-phenylethane (18O, 13C, D) establish beyond doubt that the oxygen migration accompanying the photochemical Wolff rearrangement is not the result of intermolecular processes. This is in agreement with a carbenecarbene rearrangement via an intermediate oxirene in competition to the rearrangement into a ketene, as reason for the partial
The reduction process and the nature of the reduction products were studied by NMR. Tetraphenylbenzene was reduced by both metals to yield the corresponding dianionic salt. It was found that the addition of extra charge into the system, restricted the free rotation of the four phenyl substituents about the σ bond connecting them to the central ring (G⧧181 = 7.8 ± 0.2 kcal mol-1). The reaction of the
Dissociative ionization of aryl-substituted vinyl bromides in the gas phase: experimental and computational evidence for the formation of stable .alpha.-arylvinyl cations both by direct means and by spontaneous exothermic isomerization of unstable isomeric ions