Palladium-mediated carboxylation of aryl halides (triflates) or benzyl halides using [ 13 C]/[ 11 C]carbon monoxide with tetrabutylammonium hydroxide or trimethylphenylammonium hydroxide

[Carbonyl-11C]carboxylic acids were synthesised using palladium-mediated reaction of [11C]carbon monoxide with aryl halides/triflates and benzyl halides in combination with either tetrabutylammonium hydroxide or trimethylphenylammonium hydroxide. The radiochemical yields were in the range 20-85%. In a typical experiment starting with 2.1 GBq [11C]carbon monoxide, 0.6 GBq of HPLC-purified 1-[carbonyl-11C]naphthoic acid (13) was obtained within 25 min of the start of the carbonylation reaction (67% decay-corrected radiochemical yield). The specific radioactivity of [carbonyl-11C]nicotinic acid (17) was in the order of 750 GBq µmol−1 using 10.0 µAh bombardment. [Carbonyl-13C]nicotinic acid (17) was synthesised to verify the position of the labelling (δ 166.1) determined by 13C NMR.