Using a catalytic amount of Nal and a stoichiometric oxidant Oxone-@,a convenient procedure has been developed for the catalytic oxidative 1,2-shift of arylalkenes in CH3CN/H2O at room temperature,which provides the c...Using a catalytic amount of Nal and a stoichiometric oxidant Oxone-@,a convenient procedure has been developed for the catalytic oxidative 1,2-shift of arylalkenes in CH3CN/H2O at room temperature,which provides the corresponding α-aryl ketones in moderate to good yields.In this protocol,sodium iodide is first oxidized into hypoiodous acid,which reacts with arylalkene to afford iodohydrin.Then,the iodohydrin is transformed into the α-aryl ketone via an oxidative 1,2-shift rearrangement.展开更多
A systematic calculation of the potential curves or surfaces for 1,2-shift has been realized by using MNDO or other models in MOPAC programs. By referring to the previous author’ viewpoints, the 1,2-shift can be divi...A systematic calculation of the potential curves or surfaces for 1,2-shift has been realized by using MNDO or other models in MOPAC programs. By referring to the previous author’ viewpoints, the 1,2-shift can be divided into two categories. 1,2-electron-deficient shift is that the electronic configuration of the atom which accepts the migrating group is a cation or an electron-deficient atom, and 1,2-anion shift is the one that the accepted atom of the migration group is a negative ion. In terms of the experimental facts and the calculation of the potential surfaces, in electron-deficient shift such as Beckmann or Baeyer-Villiger rearrangement, the migration occurs through a transition complex formed between the π-bond and the cation or electron-deficient migrating group, but in anion shift such as Wittig or Stevens rearrangement, the electron pair in π-orbit excites at first to π orbit, and then the migration occurs through the new formed complex between the anion migration group and the vacant π orbit. The above mechanisms explain reasonably the intramolecular properties, the configuration retentions of the migration group, and the corresponding migratory aptitudes of the two type 1, 2-shifts. The partial and less important free radical reaction of 1, 2-anion shift has been explained by the π-complex mechanism too.展开更多
基金Financial support from the National Natural Science Foundation of China(No.21072176) is greatly appreciated
文摘Using a catalytic amount of Nal and a stoichiometric oxidant Oxone-@,a convenient procedure has been developed for the catalytic oxidative 1,2-shift of arylalkenes in CH3CN/H2O at room temperature,which provides the corresponding α-aryl ketones in moderate to good yields.In this protocol,sodium iodide is first oxidized into hypoiodous acid,which reacts with arylalkene to afford iodohydrin.Then,the iodohydrin is transformed into the α-aryl ketone via an oxidative 1,2-shift rearrangement.
文摘A systematic calculation of the potential curves or surfaces for 1,2-shift has been realized by using MNDO or other models in MOPAC programs. By referring to the previous author’ viewpoints, the 1,2-shift can be divided into two categories. 1,2-electron-deficient shift is that the electronic configuration of the atom which accepts the migrating group is a cation or an electron-deficient atom, and 1,2-anion shift is the one that the accepted atom of the migration group is a negative ion. In terms of the experimental facts and the calculation of the potential surfaces, in electron-deficient shift such as Beckmann or Baeyer-Villiger rearrangement, the migration occurs through a transition complex formed between the π-bond and the cation or electron-deficient migrating group, but in anion shift such as Wittig or Stevens rearrangement, the electron pair in π-orbit excites at first to π orbit, and then the migration occurs through the new formed complex between the anion migration group and the vacant π orbit. The above mechanisms explain reasonably the intramolecular properties, the configuration retentions of the migration group, and the corresponding migratory aptitudes of the two type 1, 2-shifts. The partial and less important free radical reaction of 1, 2-anion shift has been explained by the π-complex mechanism too.
