A Molybdenum-Catalyzed Oxidative System Forming Oxazines (Hetero-Diels−Alder Adducts) from Primary Aromatic Amines, Hydrogen Peroxide, and Conjugated Dienes
作者:Eval Rud Møller、Karl Anker Jørgensen
DOI:10.1021/jo9608127
日期:1996.1.1
The development of a new molybdenum-catalyzed procedure for the formation of oxazines-hetero-Diels-Alder adducts-from primary aromatic amines, hydrogen peroxide, and conjugated dienes is presented, The method is based on a molybdenum-peroxo complex, which in the presence of hydrogen peroxide as the terminal oxidant selectively catalyzes the oxidation of primary aromatic amines to the corresponding dienophilic nitroso compounds. The molybdenum-peroxo catalyst is under the present reaction conditions not reactive toward conjugated dienes and substituents attached to the aromatic nuclei of the primary aromatic amines. Several oxazines are synthezised following this new procedure using primary aromatic amines having either electron-withdrawing or electron-donating substituents and 1,3-cyclohexadiene as the standard diene. The scope of the new procedure is also demonstrated by the preparation of several oxazines using different alkyl- and phenyl-substituted conjugated dienes and 4-chloroaniline as precursor for the dienophile. Moderate diastereomeric excesses are found when the reaction is carried out with 1-(2-aminophenyl)-ethanol and 1,3-cyclohexadiene or (E)-1-phenyl-1,3-butadiene. The stereochemical and electronic factors governing the reaction course are briefly discussed.
In Situ Generation of Nitroso Compounds from Catalytic Hydrogen Peroxide Oxidation of Primary Aromatic Amines and Their One-Pot Use in Hetero-Diels–Alder Reactions
作者:Dongbo Zhao、Mikael Johansson、Jan-E. Bäckvall
DOI:10.1002/ejoc.200700368
日期:2007.9
sulfides to sulfoxides and this catalytic system was recycled and reused in an ionic liquid.In the third example, primary aromatic amines were oxidized by H2O2 to nitrosocompounds in a selenium-catalyzed oxidation. The nitrosoarenes were used in a one-pot hetero Diels-Alder reaction with dienes forming 1,2-oxazines.In the fourth example, a cobalt salophen complex was immobilized in different zeolites