Deuterium labeling of norbornene derivatives by iridium catalyzed H/D exchange catalysis

The H/D exchange catalysis using the Ir(I) complex [TpMe2Ir(η4-2,3-dimethylbutadiene)] (TpMe2=hydridotris(3,5-dimethylpyrazolyl)borate) as the precatalyst was studied for selective deuteration of norbornene derivatives. In dependence of the norbornene substitution in 2,3 positions, selective deuteration of the norbornene double bond could be achieved. (±)-endo,exo-6-Deutero-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid diethyl ester was isolated in 82% yield.