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.