Organomediated Enantioselective 18F Fluorination for PET Applications

The first organomediated asymmetric 18F fluorination has been accomplished using a chiral imidazolidinone and [18F]N‐fluorobenzenesulfonimide. The method provides access to enantioenriched 18F‐labeled α‐fluoroaldehydes (>90 % ee), which are versatile chiral 18F 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‐[18F]fluoroglutamic acid. PET molecules: A metal‐free asymmetric 18F‐labeling reaction for an aliphatic CH bond, employing a chiral imidazolidinone as the organomediator and N‐[18F]fluorobenzenesulfonimide ([18F]NFSI) as the 18F source, is reported. The method is used to prepare the 18F‐labeled positron emission tomography (PET) radiotracer (2S,4S)‐4‐[18F]fluoroglutamic acid.