Mn-Catalyzed Electrochemical Chloroalkylation of Alkenes

Abstract

The heterodifunctionalization of alkenes is an efficient method for synthesizing highly functionalized organic molecules. In this report, we describe the use of anodically coupled electrolysis for the catalytic chloroalkylation of alkenes–a reaction that constructs vicinal C–C and C–Cl bonds in a single synthetic operation–from malononitriles or cyanoacetates and NaCl. Knowledge of the persistent radical effect guided the reaction design and development. A series of controlled experiments, including divided-cell electrolysis that compartmentalized the anodic and cathodic events, allowed us to identify the key radical intermediates and the pathway to their electrocatalytic formation. Cyclic voltammetry data further support the proposed mechanism entailing the parallel, Mn-mediated generation of two radical intermediates in an anodically coupled electrolysis followed by their selective addition to the alkene.

CV‐driven Optimization: Cobalt‐Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR

“…First, we tested the electron-releasing groups such as methyl (4-6), tertiary butyl (7), methoxyl (8), and phenolic ester (9). Substrates with electron-withdrawing substitutes, for instance, fluoro (10-11), chloro (12)(13)(14), bromo (15), trifluoromethyl (16), and cyano (17) were tolerated well. Substrates with electron-withdrawing substitutes, for instance, fluoro (10-11), chloro (12)(13)(14), bromo (15), trifluoromethyl (16), and cyano (17) were tolerated well.…”

“…5, Scheme 1). [15] Inspired by those investigations, we report the CV-driven optimization for Co-electrocatalyzed construction of chloroacetophenones with abundant and cheap feedstocks. Specifically, oxygen reduction reaction (ORR) generates highly reactive intermediate-superoxide ion O 2 À * [13] which has been employed in organic electrosynthesis in very limited examples.…”

Hexafluoro‐2‐Propanol‐Promoted Electro‐Oxidative [3+2] Annulation of 1,3‐Dicarbonyl Compounds and Alkenes

“…Electrosynthesis, which can avoid the external oxidants by employing the electrons to achieve the redox reaction, is considered as a versatile and eco‐friendly synthetic strategy and has experienced remarkable renaissance in recent years . The electrochemical alkene difunctionalization is emerging as a approach to construct C−C, C−N, C−O, C−Cl and so on . We envisioned acyclic 1,3‐dicarbonyl compounds, which has interested the chemists over the years due to the high oxidation potential of acyclic 1,3‐dicarbonyl compounds, might serve as C‐radical sources and nucleophilic oxygen sources to react with alkenes, achieving the electro‐oxidative [3+2] annulation with hydrogen evolution.…”

Recent Advances in Electrochemical Oxidative Cross‐Coupling of Alkenes with H2 Evolution

“…Except that trifluoromethyl radical and difluoromethyl radical could be involved in electrochemical difunctionalization of alkenes, benzyl malononitrile could also be oxidized to produce carbon radical via anodic oxidation. In 2019, Lin and co‐workers developed electrochemical chloroalkylation of alkenes with Mn(OTf) 2 as catalyst (Scheme ) . Mn catalyst was essential for the single‐electron oxidation procedure between benzyl malononitrile or chloride ion and electrode.…”

“…In 2019, Lin and co-workers developed electrochemical chloroalkylation of alkenes with Mn(OTf) 2 as catalyst (Scheme 8). [17] Mn catalyst was essential for the single-electron oxidation procedure between benzyl malononitrile or chloride ion and electrode. The reaction proceeded smoothly with high functional group tolerance of various aliphatic alkenes and afforded the corresponding products in moderate to good yields.…”