<i>N</i>‐Sulfonylcarboxamide as an Oxidizing Directing Group for Ruthenium‐Catalyzed C–H Activation/Annulation

Abstract

N ‐Sulfonylcarboxamides can act as both a directing group for C–H activation and an internal oxidant in the Ru‐catalyzed annulation reaction with alkynes to give isoquinolones. Of all of the N ‐sulfonylcarboxamides that were studied, the N ‐(2,6‐difluorophenyl)sulfonamide derivatives were found to be the most efficient and led to the formation of an unstable sulfinate byproduct that decomposed into 1,3‐difluorobenzene under the reaction conditions. The described isoquinolone synthesis provides an alternative to the currently known traceless annulations of hydroxamic acid and sulfoximine derivatives.