Electrochemical Synthesis of Isoxazoles and Isoxazolines via Anodic Oxidation of Oximes

Isoxazol(in)es are widely featured structural motifs in natural products, agrochemicals, and pharmaceuticals. The first intermolecular approach for a direct electrochemical synthesis from readily available aldoximes is reported. Isoxazoles and isoxazolines were obtained in yields up to 81 %. The synthesis is carried out in an undivided cell as the simplest electrochemical set-up and requires only the use of electric current as traceless oxidizing agent. The application of inexpensive and widely available electrode materials in combination with recyclable supporting electrolytes and solvents paves the path for translation of the presented reaction onto preparative scale. This is underlined by successful scale-up to multi-gram runs. Electrochemical synthesis of isoxazoles is enabled via direct anodic oxidation of readily available oximes. The easiest galvanostatic set-up in combination with inexpensive electrode materials and the recyclability of the solvent system allow for a facile synthetic strategy on up to multi-gram scale.image