Palladium-catalyzed direct C–H nitration and intramolecular C–H functionalization for the synthesis of 3-nitro-1-(phenylsulfonyl)-1H-indazole derivatives

Abstract

Described herein is a palladium-catalyzed double C(sp²)–H bond functionalization triggered by a sequential nitration/cyclization process to afford indazoles under mild reaction conditions. This transformation is achieved through chelate-assisted cleavage of two C–H bonds, and includes nitration of a sulfonyl hydrazide and intramolecular C–N bond formation.