Recent Advances in Electrochemistry for the Synthesis of N-Heterocycles

Abstract

The construction of N-heterocyclic rings represents a very important and fast-developing area of organic synthesis. In this context, electrochemistry has emerged as a mild solution for generating in situ the required electrophilic substrates, bases and nucleophiles derived from low-level and extremely stable reagents, the further application of which makes some heterocycles more accessible. In this review, we have covered the recent advances in the electrochemical synthesis of five- and six-membered N-heterocyclic compounds published from 2017 to October 2018.1 Introduction2 Electrochemical Synthesis of Five-Membered N-Containing Heterocycles2.1 Pyrrolidines2.2 Imidazoles2.3 Pyrazoles2.4 Triazoles2.5 Oxazoles2.6 Indoles2.7 Thiazoless3 Electrochemical Synthesis of Six-Membered N-Containing Heterocycles3.1 Piperidines and Pyridines3.2 Quinazolinones3.3 Benzoxazines4 Conclusions

Greener Synthesis of Pyrroloquinazoline Derivatives: Recent Advances

“…Over recent years, electrosynthesis has emerged as a powerful and sustainable method for the synthesis of small organic molecules. Due to its intrinsic ability to generate highly reactive species under mild conditions by anodic oxidation or cathodic reduction, electrosynthesis is particularly interesting for otherwise challenging transformations [56–61] …”

“…Due to its intrinsic ability to generate highly reactive species under mild conditions by anodic oxidation or cathodic reduction, electrosynthesis is particularly interesting for otherwise challenging transformations. [56][57][58][59][60][61] Recently, Liu et al developed a new method for trifluoromethyl insertion on quinazolinone derivatives under electrochemical conditions. The CF 3 group was obtained from sodium trifluoromethanesulfonate (CF 3 SO 2 Na), which is easily decomposed to generate a CF 3 radical.…”

Green Chemistry: Electrochemical Organic Transformations via Paired Electrolysis

“…To date, parallel paired electrochemical synthesis has proved useful for industrial application, especially for interesting chemical reactions that convert CO 2 gas into valuable chemicals and fuels, for example, CO reagent. 63 In 2016, Moeller and co-workers 26 36). The reaction proceeded in a divided cell equipped with a glassy carbon working electrode for both the cathode and anode in a mixture of CH 3 CN:THF:CH 3 OH/Et 4 NBF 4 as a solvent/electrolyte, under a controlled potential.…”

“…The paired reaction has been successfully utilized in industrial production, such as for the paired electrosynthesis of nylon-6,6, the parallel paired reaction for the formation of 1-butyl-4-(dimethoxymethyl)­benzene and isobenzofuran-1­(3 H )-one, the electroformation of gluconic acid and sorbitol via divergent electrolysis of glucose, the formation of glyoxylic acid via convergent paired electrolysis, the electrocatalytic convergent paired degradation of para -dinitrobenzene, the electrosynthesis of methyl ethyl ketone via linear paired electrolysis, and the use of electrogenerated azobenzene as a base to achieve ethyl hexanoate . Recently, we have published review articles emphasizing the importance of organic electrochemistry for the synthesis of heterocyclic compounds, , annulation reactions, alkyne functionalization, alkene difunctionalizations, and electrochemical phosphorylation of organic compounds . In 1999, Chou and co-workers reviewed the types of paired electrolysis .…”

Non-metal-mediated N-oxyl radical (TEMPO)-induced acceptorless dehydrogenation of N-heterocycles via electrocatalysis

“… 10 More recently, TEMPO has been extensively used as a catalyst cooperating with electrocatalysis in CAD which is a green and atom-economical alternative. 11 In general, the electrochemical reaction with electrons as the oxidizing/reducing agent can be performed at room temperature without the use of chemical oxidants, which makes it safe and low cost. 12 Recently, Gong's group has developed an electrochemical dehydrogenation method for synthesis of quinazolin-4(3 H )-ones under metal-free and oxidant-free conditions by combining acid-catalyzed annulation and TEMPO as the catalyst.…”