Three-Component 1,2-Dioxygenation of 1,3-Dienes Using Carboxylic Acids and TEMPO

A mild, metal-free 1,2-dioxygenation of 1,3-dienes using TEMPO and carboxylic acids is reported. This method includes examples for a variety of 1,3-dienes as well as aliphatic and aromatic carboxylic acids. This reaction also demonstrates complete site- and regioselectivity in the oxygen addition. Furthermore, extensive derivatization of the differential oxygen groups in the product has been demonstrated, including reduction of the remaining alkene to access alkyl, vicinally dioxygenated scaffolds. Finally, this reaction is shown both experimentally and computationally to occur through carboxylic acid-driven disproportionation of TEMPO.