18F-Labeling Using Click Cycloadditions

Abstract EN

Due to expanding applications of positron emission tomography (PET) there is a demand for developing new techniques to introduce fluorine-18 (t1/2=109.8 min).

Considering that most novel PET tracers are sensitive biomolecules and that direct introduction of fluorine-18 often needs harsh conditions, the insertion of 18F in those molecules poses an exceeding challenge.

Two major challenges during 18F-labeling are a regioselective introduction and a fast and high yielding way under mild conditions.

Furthermore, attention has to be paid to functionalities, which are usually present in complex structures of the target molecule.

The Cu-catalyzed azide-alkyne cycloaddition (CuAAC) and several copper-free click reactions represent such methods for radiolabeling of sensitive molecules under the above-mentioned criteria.

This minireview will provide a quick overview about the development of novel 18F-labeled prosthetic groups for click cycloadditions and will summarize recent trends in copper-catalyzed and copper-free click 18F-cycloadditions.