Organomediated Enantioselective (18)F†Fluorination for PET Applications.

The first organomediated asymmetric (18)F fluorination has been accomplished using a chiral imidazolidinone and [(18)F]N-fluorobenzenesulfonimide. The method provides access to enantioenriched (18)F-labeled α-fluoroaldehydes (>90% ee), which are versatile chiral (18)F synthons for the synthesis of radiotracers. The utility of this process is demonstrated with the synthesis of the PET (positron emission tomography) tracer (2S,4S)-4-[(18)F]fluoroglutamic acid.

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 SN2-based radiochemistry. To date, both transition metal complexes and organomediators have been successfully employed for 18F-incorporation at a stereogenic carbon.