Co(salen)-mediated enantioselective radiofluorination of epoxides. Radiosynthesis of enantiomerically enriched [18F]F-MISO via kinetic resolution

The first example of transition metal mediated enantioselective radiofluorination of epoxides is reported. The procedure utilizes gaseous [F-18]HF in a combination with (-)tetramisole and (R,R)-Co(salen), giving the corresponding (S,S)-F-18-fluorohydrines in 78-93% radiochemical yield (RCY) and 20-46% enantioselectivities (ee). The use of this methodology allowed for a single step radiosynthesis of [F-18]F-MISO, which took 1.5 h and after solid phase-based purification delivered [F-18]F-MISO in 81%/45% analytical/preparative RCY and 55% ee. (C) 2013 Elsevier B.V. All rights reserved.