DEUTERIUM-EXCHANGE LABELING OF SUBSTITUTED AROMATICS USING [IRH2(ME2CO)2(PPH3)2]BF4

Deuterium exchange labelling experiments were conducted on several series of compounds, including para-substituted benzoate esters, para-substituted N,N-dimethylbenzamides, and mono-para-substituted benzophenones, using [IrH2(Me2CO)2(PPh3)2]BF4 as catalyst and deuterium gas as the source of isotope. In most cases, labelling was efficient and regioselective, with deuterium appearing in the positions ortho to the carbonyl-containing functional group. Apparent from the results of these experiments was that, in each case the para-substituted rings were labelled more rapidly or to a greater extent than the corresponding unsubstituted rings, regardless of the identity of the substituent.