Catalytic Activation of Nitrogen Dioxide for Selective Synthesis of Nitroorganics.

摘要

The use of modern metal-catalyzed methods for production of nitroorganics has been impeded by the paucity of fundamental data on organometallic nitro compounds. Nitrotrimethylplatinum(IV) undergo reductive elimination reactions to form C-O and C-N bonds, at rates and by mechanisms similar to those previously observed for the corresponding acetate complexes. The reactions are unusually selective for C-O bond formation, forming more methyl nitrite than nitromethane. Arylpalladium(II) nitrites are formed as mixtures of O- and N-bonded compounds. Reductive elimination of the nitro group from these compounds is seldom observed, with C-P and C-C reductive elimination of ancillary phosphine ligands taking place preferentially, though traces of nitroarene are observed on thermolysis of (dppf)Pd(Ar)(NO2). Formation of Pd(IV) aryl compounds through oxidative addition of N2O4 has also been observed, though reductive elimination of the nitroarene has not. Nitrogen dioxide can be used as a source of the nitro group in reactions with arylboronic acids or their pinacol esters. In some cases, no catalyst is necessary, but in electron-rich systems catalysts (preferredly IrCl3(py)3) are needed to divert reactivity from electrophilic nitration to ipso nitro-deboronation.