Practical Synthesis of Halogenated N‐Heterocycles via Electrochemical Anodic Oxidation of Unactivated Alkenes

Abstract

A general and efficient intramolecular halo‐amination of unactivated alkenes for the synthesis of various halogenated N‐heterocycles was developed via electrochemical anodic oxidation. This protocol proceeds in a simple undivided cell by employing LiI or LiBr as redox mediums and halogen sources. A wide range of halogenated N‐heterocycles, including three‐, five‐, and six‐membered N‐heterocycles were constructed in moderate to good yields at room temperature. Notably, this electrochemical oxidative transformation avoids the utilization of external oxidants and strong bases, therefore represents an environmentally benign approach.

Transition-Metal-Catalyzed Carbonylative Multifunctionalization of Alkynes

“…Substituted maleimides and succinimides represent an interesting class of bioactive N -heterocycles , that show various biological activities including antibacterials, cytotoxicities, inhibition of different kinases, and so on. Owing to these interesting biological properties, the development of efficient methods for the synthesis of maleimide and succinimide derivatives has attracted considerable interest.…”

“…Then the intermediate A was inserted into the alkyne to give the vinylrhodium(I) complex B, which went through oxidative addition of C−Br on the adjacent phenyl ring to afford the rhodium(III) species C. Finally, the insertion of CO in C followed by reductive elimination gave the target indenones. Substituted maleimides and succinimides represent an interesting class of bioactive N-heterocycles 38,39 that show various biological activities including antibacterials, 40 cytotoxicities, 41 inhibition of different kinases, 42 and so on. Owing to these interesting biological properties, the development of efficient methods for the synthesis of maleimide and succinimide derivatives has attracted considerable interest.…”

Electrochemical Bromofunctionalization of Alkenes and Alkynes—To Sustainability and Beyond

“…Yin and co-workers introduced an oxidant-and base-free electrochemical intramolecular halo-amination of unactivated alkenes to form diverse brominated N-heterocycles [91]. They provide a simple electrochemical protocol using bench-stable LiBr or LiI as a halide source and a supporting electrolyte furnishing a dual role.…”

“…Scheme 7. Electrochemical intramolecular haloamination with the aid of LiBr and LiI[91]. Cgr = graphite.…”

Synthesis of 3-chloropiperidines by iodide-mediated electrolysis

“…23,24 This has resulted in a wide variety of methods for cyclization reactions, especially for the formation of aziridines [25][26][27] and pyrrolidines. 28 Recently, Yin and coworkers 28 offered an iodine mediated approach for the efficient cyclization of non-acti-vated aminoalkenes to iodomethylpyrrolidines. Their mechanistic proposal includes the electrophilic addition of iodine to a double bond with a consecutive ring closure to form the respective iodomethylpyrrolidine scaffold.…”