Palladium catalyzed N-arylation of hydroxylamines

Over the past decade modified Ullmann couplings and palladium-catalyzed arylations of nitrogen contg. compds. (Buchwald-Hartwig aminations) have emerged as powerful tools in synthetic chem. Interestingly, despite their biol. and synthetic significance, only three reports of cross couplings of hydroxylamines have been disclosed. This lack of investigation is surprising as N-aryl hydroxylamines are valuable intermediates in the prepn. of important nitrogen heterocycles including indoles, isoxazolidines oxadiazolidinones and aziridines. Within the poster we present a mild and efficient palladium catalyzed method for the prepn. of N-aryl hydroxylamines. The scope and limitations of the procedure will be detailed and methods for the selective deprotection of both the N- and O-functionality described allowing full advantage of this important functional group to be revealed.