Benjamin P. Vokits

Sulfonyl hydrazides are stable and usually crystalline substances that can be accessed in a variety of ways, including transiently from hydrazones, to achieve a net reductive arylation of carbonyl compounds. We show their utility as versatile radical precursors, as exemplified with seven C–C bond–forming, redox-neutral cross-couplings with activated olefins, alkyl halides, redox-active esters, aryl halides, alkenyl halides, alkynyl halides, and a trifluoromethylating reagent, to forge C(sp ³ )-C(sp ³ ), C(sp ³ )-C(sp ² ), and C(sp ³ )-C(sp) bonds. Exogenous redox (chemical, photo/electrochemical) additives are not necessary because these functional groups serve the dual role of radical precursor and electron donor. The homogeneous, water-compatible reaction conditions are operationally simple and contribute to streamlining synthesis and mild late-stage functionalization.

Disclosed herein is the invention of a method for facile C–H alkylation of a range of (hetero)arenes under Ni-catalysis. This reaction takes place at 50 °C, is scalable, tolerates heterocyclic substrates, and can be applied to both primary and complex secondary alkyl donors. Success hinges on the use of sulfonylhydrazide-based alkyl donors that mildly generate alkyl radicals thereby obviating the need for alkyl halide precursors that require more harsh conditions to activate. The demonstrated substrate scope is broad (>70 examples), and the reaction was also applied to natural product synthesis. Mechanistic studies (both computational and experimental) suggest that an asynchronous, amine-assisted C–H activation pathway is operative which may have larger implications for the field.