Enantioselective Radiosynthesis of Positron Emission Tomography (PET) Tracers Containing [18F]Fluorohydrins

Herein, we describe an operationally straightforward radiosynthesis of a chiral transition metal fluoride catalyst, [F-18](salen)CoF, and its use for late-stage enantioselective aliphatic radiofluorination. We demonstrate the utility of the method by preparing single enantiomer experimental and clinically validated PET tracers that contain base-sensitive functional groups, epimerizable stereocenters, and nitrogen-rich motifs. Unlike the conventional radiosyntheses of these targets with [F-18]KF, labeling with (salen)CoF is possible in the last step and under exceptionally mild conditions. These results constitute a rare example of a nucleophilic radiofluorination using a transition metal fluoride and highlight the potential of such reagents to enhance traditional methods for labeling aliphatic hydrocarbons.