Catalyst‐Free Oxytrifluoromethylation of Alkenes through Paired Electrolysis in Organic‐Aqueous Media

Abstract

A mild, catalyst‐free electrochemical oxytrifluoromethylation of alkenes has been developed. The procedure is based on the paired electrolysis of sodium triflinate and water in an undivided cell. Anodic oxidation of the triflinate anion generates trifluoromethyl radicals that react with the alkene. Water plays a dual role as oxidant for the cathode and nucleophile. The method has been utilized to prepare a diverse set of 1‐hydroxy‐2‐trifluoromethyl compounds in moderate to excellent yields (27–94 %). Alcohols have also been tested as nucleophiles for this versatile method with moderate yields. Facile recycling of the electrolyte has been demonstrated, and application of electricity avoids the use of stoichiometric amounts of oxidizers in a safe and environmentally benign reaction.

Direct Arylation of α‐Amino C(sp3)‐H Bonds by Convergent Paired Electrolysis

“…In contrast to normal electrochemical process, which only involve either the anodic or cathodic reaction, paired electrolysis simultaneously matches the two desirable half reactions, thus furnishing one or more products . In partucular, convergent paired electrolysis,– in which the intermediates formed at anode and cathode interact with each other to yield the final product, is an efficient approach to perform cross‐coupling reactions. From the perspective of retrosynthesis for the arylation of α‐amino sp 3 C−H bonds, we can divide the coupling produces into two parts: dehydrogenation of amines and reduction of aryl precursors, such as halogenated aromatics and benzonitriles.…”

Electrochemical Decarboxylative Trifluoromethylation of α, β‐Unsaturated Carboxylic Acids with CF3SO2Na

“…In this study, CF 3 radical was generated from the anodic oxidation of CF 3 SO 2 K. Subsequently, Baran's group chose Zn(SO 2 CF 3 ) 2 as a source of trifluoromethyl radical and accomplished the trifluoromethylation of heteroarenes under electrochemical conditions in 2014 . Further, the works on trifluoromethylative difunctionalization of alkenes by electrolysis of CF 3 SO 2 Na were disclosed by Cantillo, Lin, Lei, Xu, Pan, and Kim, respectively. Meanwhile, the electrochemical trifluoromethyl/cyclization of N ‐arylacrylamides with CF 3 SO 2 Na have also been demonstrated by Zeng, Mo, and Ackermann, respectively.…”

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

“…Alcohol, acid, pyrazole, acetonitrile could all be tolerated successfully. Analogously, in 2018, Kappe, Cantillo and co‐workers developed an electrochemical oxytrifluoromethylation of alkenes in organic‐aqueous media …”

“…Analogously, in 2018, Kappe, Cantillo and co-workers developed an electrochemical oxytrifluoromethylation of alkenes in organicaqueous media. [12] Mechanistically, the EPR experiments have been done to identify the CF 3 radical signal. And the cyclic voltammetry experiments also indicated the CF 3 SO 2 Na was likely to be first oxidized under electrolytic conditions.…”