Electrochemical-Promoted Nickel-Catalyzed Oxidative Fluoroalkylation of Aryl Iodides

Abstract

This work describes a general strategy for metalcatalyzed cross-coupling of fluoroalkyl radicals with aryl halides under electrochemical conditions. The contradiction between anodic oxidation of fluoroalkyl sulfinates and cathodic reduction of low-valent nickel catalysts can be well addressed by paired electrolysis, allowing for direct introduction of fluorinated functionalities into aromatic systems.

Progress in Convergent Paired Electrolysis

“…Two main strategies have been developed to allow the in-situ generation of alkyl radical. In the work of Hu and Liu (pathway A), benzylic radicals (23) were produced by direct anodic oxidation of toluene derivatives and benzylic trifluoroborates, respectively. In contrast, in reports from Li and co-workers (pathway B), alcohols were transformed into alkyl bromides (25) through an anodic Appel reaction, which was then followed by nickel-catalyzed SET to afford alkyl radicals (26).…”

“…Inspired by the strategies based on nickel catalysis shown above, some more recent exciting developments have been reported. The nickel‐catalyzed fluoroalkylation of aryl iodides was developed by the Wang group under convergent paired electrolysis conditions [23] . Sulfinates were unveiled as alternative thiolation reagents by Zhang with nickel catalysis strategy [24] .…”

“…The nickel-catalyzed fluoroalkylation of aryl iodides was developed by the Wang group under convergent paired electrolysis conditions. [23] Sulfinates were unveiled as alternative thiolation reagents by Zhang with nickel catalysis strategy. [24] Ye and co-workers have described a redox-neutral coupling between an amine α-CÀ H with aryl bromides by using a strategy of nickel-enabled convergent paired electrolysis.…”

Recent Advances in C(sp3)–C(sp3) and C(sp3)–C(sp2) Bond Formation through Cathodic Reactions: Reductive and Convergent Paired Electrolyses

“…In 2020, Hu et al established a Ni-catalyzed electrochemical redox-neutral cross-coupling between toluene derivatives 247 and (hetero)­aryl bromides 246 . , This attractive benzylic C­(sp 3 )–H arylation proceeded under mild constant current electrolysis but required a specific fluorine-doped tin oxide-coated glass anode. Electron-rich as well as electron-poor aryl bromides 246 were suitable coupling partners for this transformation.…”

Electrochemical Dearomatization of Indoles: Access to Diversified Fluorine-Containing Spirocyclic Indolines

“…To demonstrate the generality of this electrochemical protocol, another fluorine source (NaSO 2 CF 2 H) was tested (Scheme ). To our best knowledge, although CF 2 H radical addition to an alkene or alkyne induced by electrochemistry has been achieved, the reactivity of the indole ring is still obscure. ,, Interestingly, when NaSO 2 CF 2 H served as the fluorine source, the desired compound 3a was isolated in an acceptable yield in constant voltage mode. Different substituents at the C5 position were well-tolerated, delivering the expected compounds in moderate yields ( 3b , 58%; 3c , 46%).…”