Platinum on Carbon‐Catalyzed H–D Exchange Reaction of Aromatic Nuclei due to Isopropyl Alcohol‐Mediated Self‐ Activation of Platinum Metal in Deuterium Oxide

Abstract An efficient and simple deuteration method of arenes using the platinum on carbon‐isopropyl alcohol‐cyclohexane‐deuterium oxide combination under hydrogen gas‐free conditions was accomplished. Since the hydrogen–deuterium exchange reaction cannot be promoted without isopropyl alcohol, zerovalent platinum metal (on carbon) is self‐activated by the in situ ‐generated very low amount of hydrogen or hydrogen–deuterium gas derived from isopropyl alcohol or isopropyl alcohol‐ d 1 . Deuterium‐labeled compounds with high deuterium contents can be easily isolated by the filtration of platinum on carbon and simple extraction. The present hydrogen gas‐free method is safe from the viewpoint of process chemistry and various arenes possessing a variety of reducible functionalities within the molecule could be effectively and directly deuterium‐labeled without undesired reduction.