Iridium-catalysed labelling of anilines, benzylamines and nitrogen heterocycles using deuterium gas and cycloocta-1,5-dienyliridium(I) 1,1,1,5,5,5-hexafluoropentane-2,4-dionate

Iridium‐Catalyzed H/D Exchange

“…This finding parallels the experiments of Hickey et al, [15] in which 4-aminobenzoic acid was labelled with D 2 in the meta position rather than in the ortho position In this case the results were explained by formation of an iridium colloid cluster that is able to exchange in positions other than ortho.…”

Preparation of Tritium‐Labeled Compounds by Isotope Exchange Reactions

“…Modest success has been achieved in some model studies, mostly using the same catalyst 219,220 , but positive results have been sporadic and no particular system has been found to be widely useful. The iridium dionate class of catalysts (next section) are much more effective for labeling such substrates.…”

“…In what may be a mechanistically different process, mono-, di-, and even trisubstituted benzylamines, as well as anilines, were found to be deuterated 219,220 in ortho positions from deuterium gas by use of the catalyst precursor cyclooctadienyliridium 1,1,1,5,5,5-hexafluoropentane-2,4-dionate ((cod)Ir(hfpd)). This neutral complex, with an anionic O,O 0bidentate ligand, was the most active of three related ones tested.…”

Organoiridium complexes for hydrogen isotope exchange labeling

“…Although first tested with D 2 O as the source of isotope, the investigators found that they work with a similar range of substrates using D 2 gas and DMF or DMA solvent. 29 30,31 use of tritium gas was reported on two substrates. 31 The regioselectivity of this labeling is not guided by coordinating functional groups (except perhaps by coordinating substituents such as halo, hydroxyl 32 ), but rather is sensitive to the steric environment, so that the positions labeled tend to be different from those with the other catalyst types.…”