Electrophotocatalytic Reductive 1,2‐Diarylationof Alkenes with Aryl Halides and Cyanoaromatics

Abstract

Comprehensive Summary The radical‐mediated reductive functionalization of aryl halides has been extensively studied. However, the related radical‐mediated intermolecular reductive 1,2‐diarylation of alkenes, using aryl halides as aryl radical sources, remains unexplored. Herein, a new electrophotocatalytic intermolecular reductive 1,2‐diarylation of alkenes is reported using aryl halides and cyanoaromatics to produce polyarylated alkanes. Using synergistic cathodic reduction and visible‐light photoredox catalysis, various electron‐rich and electron‐deficient aryl halides are combined with various alkenes and cyanoaromatics to characterize the broad substrate scope, excellent functional group compatibility, and excellent selectivity of this reaction. Mechanistic investigations reveal that this reaction may proceed via a radical process initiated by the reductive generation of aryl radicals from aryl halides and terminated by radical‐radical coupling with cyanoaromatic radical anions.

Recent Advances in Reactions Involving Carbon Dioxide Radical Anion

“…Recently, Li and co-workers developed an electrophotocatalytic intermolecular reductive 1,2-diarylation of alkenes using synergistic photoredox catalysis and cathodic reduction (Scheme 20). 34 Aryl halides possessing electron-rich and electron-deficient groups were combined with alkenes and cyanoaromatics to feature a broad substrate scope. A possible mechanism was outlined as shown in Scheme 20.…”

Recent Advances in the 1,2‐Diarylation of Alkenes

“…Reductive electro photocatalytic approaches are promising because they combine electrochemical and photochemical energy to obtain exceptionally high reduction potentials under catalyst control. Zeng and co-workers [45] have reported the discovery of a groundbreaking electro-photocatalytic three-component re-ductive alkene 1,2-DIAR reaction utilizing aryl halides and cyanoaromatics (Scheme 30). This method demonstrates a wide range of substrate scope, exceptional compatibility with various functional groups, and remarkable selectivity in this reaction.…”

Photoredox-Catalyzed Three-Component 1,2-Cyanoalkylpyridylation of Styrenes with Nonredox-Active Cyclic Oximes

“…In this context, elegant two-component radical-involved reactions for the synthesis of alkylpyridines have recently been well exploited, including the classical Minisci reaction as well as visible-light-induced C–C coupling reaction from the groups of MacMillan, Jui, Zhu, etc . On the other hand, the three-component radical-involved reaction mode, especially alkene 1,2-difunctionalizations, , has emerged as a powerful and versatile strategy for rapid buildup of diverse and complex functionalized alkylpyridines that are otherwise hard to synthesize owing to the simultaneous introduction of pyridines and another important functionality from simple and accessible starting materials in a single-pot operation. Despite some elegant advancements achieved by employing this powerful three-component strategy, to the best of our knowledge, the distal functionalized alkyl radicals for the three-component alkene 1,2-alkylpyridylations were still rare.…”