Selective hydrogen isotope exchange on sulfonamides, sulfilimides and sulfoximines by electrochemically generated bases

We present a mild, metal-free electrochemical method to selectively add deuterium to the position α of the sulfur atom in sulfonamides, sulfilimides, and sulfoximines using a simple two-electrode setup under galvanostatic conditions. Our method is based on readily available NMR solvent DMSO-<i>d</i>₆ as the deuterium source and reusable glassy carbon electrodes. A low current density ensures functional group tolerance and enables selective incorporation of deuterium into pharmaceutically relevant moieties. With deuterium incorporation up to 97% the method stands out as a new possibility to label molecules electrochemically without the use of toxic and expensive transition-metal catalysts.