Carbon-11 carboxylation of terminal alkynes with [11C]CO2

A copper-catalysed radiosynthesis of carbon-11 radiolabelled carboxylic acids was developed by reacting terminal alkynes and cyclotron-produced carbon-11 carbon dioxide ([C-11]CO2) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). A small library of C-11-labelled propiolic acid derivatives were obtained with a total synthesis time of 15 min from end of bombardment (EOB) with a (non-isolated) radiochemical yield ranging from 7% to 28%.

Automated summary

A copper-catalysed radiosynthesis was developed to obtain carbon-11-labelled carboxylic acids by reacting terminal alkynes with cyclotron-produced carbon-11 carbon dioxide in the presence of DBU. This method resulted in a small library of C-11-labelled propiolic acid derivatives with radiochemical yields ranging from 7% to 28% in a total synthesis time of 15 min from end of bombardment (EOB).