Nickel-Catalyzed N-Arylation of Sulfinamides: A Comparative Study versus Analogous Sulfonamide Cross-Couplings

Abstract

Despite recent progress regarding the metal-catalyzed C–N cross-coupling of (hetero)aryl (pseudo)halides with NH substrates, such transformations involving sulfinamide nucleophiles are underdeveloped. Herein we report on Ni-catalyzed C–N cross-couplings of this type, employing primarily tert-butanesulfinamide (i.e., Ellman’s sulfinamide) as a test nucleophile. Inexpensive and abundant (hetero)aryl chlorides proved to be suitable reaction partners in such reactions when using (L)Ni(o-tol)Cl (L = CyPAd-DalPhos or PhPAd-DalPhos) precatalysts. We also present results of an experimental and computational study focusing on C–N reductive elimination involving newly prepared and isolated sulfinamido (L)Ni(o-tol)(NHS(O)tBu) complexes, in which deprotonation leading to the formation of the putative anionic nitrene species [(L)Ni(o-tol)(NS(O)tBu)]− represents the preferred pathway for C–N reductive elimination, in keeping with our past study of related sulfonamido complexes.