Scientists from Zelinsky Institute for the first time carried out oxidative coupling reaction with electrochemically generated N-oxyl radicals

Short-lived highly reactive radical species often act as intermediates in electrochemical reactions. They play a key role in the formation of new chemical bonds. The electrochemical generation and synthetic use of O-centered N-oxyl radicals is complicated by their low stability and tendency to decomposition when exposed to electric current.

Researchers from laboratory № 13 of Zelinsky Institute demonstrated that the generated from N-hydroxyphthalimide in undivided electrochemical cell radicals did not decompose, but selectively entered into an oxidative coupling with vinyl azides. The reaction products are O-phthalimidoximes with an unusual N-O-N structural fragment. Scientists have proven that the process can be scaled up and have obtained a wide variety of various O-phthalimidoximes. Special attention was paid to the investigation of the presumable mechanism. Using cyclic voltammetry and EPR spectroscopy, researchers confirmed the formation of phthalimide-N-oxyl radicals under reaction conditions and their participation in the target process. The developed approach opens up great opportunities for the selective introduction of a valuable hydroxylamine fragment into various organic molecules under electrochemical conditions.

Source:

Stanislav A. Paveliev, Artem I. Churakov, Liliya S. Alimkhanova, Oleg O. Segida, Gennady I. Nikishin, Alexander O. Terent'ev Electrochemical Synthesis of O-Phthalimide Oximes from α-Azido Styrenes via Radical Sequence: Generation, Addition and Recombination of Imide-N-Oxyl and Iminyl Radicals with C−O/N−O Bonds Formation. Adv. Synth. Catal. 2020, accepted manuscript, DOI: 10.1002/adsc.202000618.