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

The H/D exchange catalysis using the Ir(I) complex Tp^Me₂Ir(η⁴-2,3-dimethylbutadiene)] (Tp^Me₂=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-bicyclo2.2.1]hept-5-ene-2,3-dicarboxylic acid diethyl ester was isolated in 82% yield.