Nickel‐Catalyzed N‐Arylation of NH‐Sulfoximines with Aryl Halides via Paired Electrolysis

Abstract

A novel strategy for the N‐arylation of NH‐sulfoximines has been developed by merging nickel catalysis and electrochemistry (in an undivided cell), thereby providing a practical method for the construction of sulfoximine derivatives. Paired electrolysis is employed in this protocol, so a sacrificial anode is not required. Owing to the mild reaction conditions, excellent functional group tolerance and yield are achieved. A preliminary mechanistic study indicates that the anodic oxidation of a NiII species is crucial to promote the reductive elimination of a C−N bond from the resulting NiIII species at room temperature.

Transition metal-catalyzed organic reactions in undivided electrochemical cells

“…Recently, Mei and co-workers developed a nickel-catalyzed N-arylation of NH-sulfoximines using aryl halides via paired electrolysis under very mild conditions (Figure 6b). 40 For comparison, non-electrochemical copper-catalyzed reactions involving aryl chlorides are slow, although aryl bromides perform similarly. These reports show that the electrochemical reaction has great advantages compared to the traditional conditions.…”

“…6b ). 40 In comparison, non-electrochemical copper-catalyzed reactions involving aryl chlorides are slow, although aryl bromides perform similarly. These reports show that the electrochemical reaction has great advantages compared to the traditional reactions.…”

Nickel-Catalyzed Paired Electrochemical Cross-Coupling of Aryl Halides with Nucleophiles

“…alkoxides) was not needed. 48,49 The substrate scope of this reaction was relatively broad; for instance, aryl bromides bearing an ester (28a), a methoxy (28b), and a trifluoromethyl group (28d) were demonstrated to be viable coupling partners, and the desired N-arylation products could be afforded in good yields. In terms of sulfoximines, both electron-rich (28a, 28b, 28c) and electron-deficient (28f) sulfoximines were amenable to this reaction, and the desired products were produced in goodto-excellent yields (Scheme 14).…”

“…In 2021, the Mei group reported an electrochemically enabled, nickel-catalyzed N-arylation of NH-sulfoximines with aryl halides (Scheme 14). 48 The reaction conditions of this transformation were mild (room temperature reaction), and the presence of strong bases (e.g. alkoxides) was not needed.…”

Electrochemical dehydrogenative C–N coupling of hydrazones for the synthesis of 1H-indazoles

“…16 Very recently, the Mei group reported a strategy for the N-arylation of NH-sulfoximines by merging nickel catalysis and electrochemistry. 17 Although, as early as 1979, the Caullet group reported a method for synthesizing indazoles by the electrochemical oxidation of hydrazones, there were only two examples reported with 30% yields. 18 With our continued interest in developing environmentally friendly methodologies for the synthesis of heterocyclic compounds, 19-21 herein, we report a scalable electrochemical dehydrogenative C-N coupling protocol for the synthesis of diverse 1H-indazoles under metal-and oxidant-free conditions with wide substrate scopes and good to excellent yields (Scheme 1c).…”