Electrochemical oxo-functionalization of cyclic alkanes and alkenes using nitrate and oxygen.

Nikl, Joachim; Hofman, Kamil; Mossazghi, Samuel; Möller, Isabel C; Mondeshki, Daniel; Weinelt, Frank; Baumann, Franz-Erich; Waldvogel, Siegfried R · Nat Commun · 2023

basic_science · Level V

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Abstract

Direct functionalization of C(sp3)-H bonds allows rapid access to valuable products, starting from simple petrochemicals. However, the chemical transformation of non-activated methylene groups remains challenging for organic synthesis. Here, we report a general electrochemical method for the oxidation of C(sp3)-H and C(sp2)-H bonds, in which cyclic alkanes and (cyclic) olefins are converted into cycloaliphatic ketones as well as aliphatic (di)carboxylic acids. This resource-friendly method is based on nitrate salts in a dual role as anodic mediator and supporting electrolyte, which can be recovered and recycled. Reducing molecular oxygen as a cathodic counter reaction leads to efficient convergent use of both electrode reactions. By avoiding transition metals and chemical oxidizers, this protocol represents a sustainable oxo-functionalization method, leading to a valuable contribution for the sustainable conversion of petrochemical feedstocks into synthetically usable fine chemicals and commodities.