Economical, Green, and Safe Route Towards Substituted Lactones by Anodic Generation of Oxycarbonyl Radicals

Abstract

An ew electrochemical methodology has been developed for the generation of oxycarbonyl radicals under mild and green conditions from readily available hemioxalate salts.M ono-and multi-functionalised g-butyrolactones were synthesised through exo-cyclisation of these oxycarbonyl radicals with an alkene,f ollowed by the sp 3 -sp 3 capture of the newly formed carbon-centred radical. The synthesis of functionalised valerolactone derivatives was also achieved, demonstrating the versatility of the newly developed methodology.T his represents av iable synthetic route towards pharmaceutically important fragments and further demonstrates the practicality of electrosynthesis as ag reen and economical method to activate small organic molecules.

Organic electrosynthesis: from academia to industry

“…This reaction is known as the Hofer-Moest reaction (Scheme 3). [23][24][25][26] Indeed, these conditions have proven useful for the synthesis of homo-and hetero-dimers alongside, more recently, phthalides, 27 γ-butyrolactones, 28…”

Bridging Lab and Industry with Flow Electrochemistry

“…Organic electrosynthesis is re-emerging as an attractive approach for conducting organic reactions in an environmentally responsible manner ( Blanco et al., 2019 ; Petti et al., 2019 ). When it comes to academia, organic electrosynthesis can be considered as a viable and better way of conducting oxidation and reduction reactions with higher yields, selectivity, and purity ( Yan et al., 2017 ).…”

Anodically‐Generated Alkyl Radicals Derived from Carboxylic Acids as Reactive Intermediates for Addition to Alkenes

“…The synthesis of such RR products by radical self‐coupling is still not economically attractive, but using the R⋅ intermediates to react with a second reactant may be of interest because higher value product can be pursued. Previous studies have used carboxylic acids as substrates to electrochemically produce alkenes, [33] ethers, [34] cyclic hydrocarbons, [35] lactones, [36] anhydrides, [37] and amides [38] . Radical addition to alkenes is particularly interesting, [39–45] as it enables C−C coupling that results in asymmetrical products (Scheme 1a).…”