Perdeuteration of Arenes via Hydrogen Isotope Exchange Catalyzed by the Superbasic Sodium Amide Donor Species NaTMP·PMDETA.

Abstract

Hydrogen isotope exchange (HIE) has become one of the most studied methods to prepare deuterated molecules, with the primary focus recently on metal-catalyzed C-H activation with transition metals. Here we report the use of a simple sodium amide, NaTMP (TMP = 2,2,6,6-tetramethylpiperidide), combined with tridentate Lewis donor PMDETA (N,N,N',N″,N″-pentamethyldiethylenetriamine), which is able to catalytically promote the HIE of a series nonactivated arenes under mild reaction conditions using C6D6 as the deuterium source. Establishing the potential of NaTMP for the deuteration of aromatic molecules, several nonactivated substrates such as naphthalene, diphenylacetylene, and stilbene could be deuterated under mild reaction conditions without the need of transition metals. Combining NMR studies with the isolation of key organometallic intermediates, we demonstrate that the ability of NaTMP/PMEDTA to partially metalate C6D6, with concomitant generation of TMP(D), is key to enable the catalytic deuteration.