Facile alpha-Ketonization of Carbonyl Compounds Utilizing CuBr_2 on Alumina

摘要

Many interests have been drawn for alpha-diketones due to their utility as an important precursor of biological and organic synthesis. Several methodologies are known for the preparation of the diketones and new methods are being continuously updated. The best known procedures are oxidation of alpha-methylene ketones to alpha-diketones using various oxidants such as selenium dioxide, pyridinium chloro-chromate (PCC), or potassium permanganate. Multi step approaches are also known like alpha-halogenation of ketones followed by the Kornblum oxidation of the haloketones using DMSO. Recently a few other methods such as a microwave promoted oxidation or a nitrosation method6 have been added to the list of diketone synthesis. Even though various methodologies toward synthesis of alpha-di-ketones have been developed as described above, most of these methods still require harsh reaction conditions or rather exotic environment.