Asymmetric ¹⁸F-fluorination for applications in positron emission tomography

Positron emission tomography (PET) is becoming more frequently used by medicinal chemists to facilitate the selection of the most promising lead compounds for further evaluation. For PET, this entails the preparation of ¹¹C- or ¹⁸F-labeled drugs or radioligands. With the importance of chirality and fluorine substitution in drug development, chemists can be faced with the challenge of preparing enantiopure molecules featuring the ¹⁸F-tag on a stereogenic carbon. Asymmetric ¹⁸F-fluorination is an emerging field of research that provides an alternative to resolution or conventional S_N2-based radiochemistry. To date, both transition metal complexes and organomediators have been successfully employed for ¹⁸F-incorporation at a stereogenic carbon.