Organocatalyst-assisted Ar–¹⁸F bond formation: a universal procedure for direct aromatic radiofluorination

Abstract

A metal free, phosphane-catalysed protocol for C-F bond formation based on ipso-elimination of iodanes is described. The reaction proceeds in significantly higher yield and with markedly reduced variability of yields (yield range) than previously described procedures. Rapid and efficient radiofluorination is achieved using unobjectionable chemical reagents with precedence in routine radiotracer production. With operational ease and mild conditions, the method promises a high potential for radiolabelling of biomolecules.

Formamide as an Unconventional Amine Protecting Group for PET Radiochemistry

“…Radiofluorination of all non‐activated substrates was achieved from the corresponding iodonium ylide precursor in excellent conversion (87 ± 10 %, n = 114, radioTLC) with high reproducibility in between both, individual runs and batches under standard radiofluorination conditions[3a] and without radioactive side products (Scheme ).…”

“…The available strategy for avoiding oxidation, protonation via strong acids only works occasionally and is incompatible with sensitive functional groups. Hypervalent iodane nucleofuges are the only transition metal free methodology that consistently provides radiofluorination of both deactivated and sterically hindered positions in good yields …”

Chemistry for Positron Emission Tomography: Recent Advances in 11C‐, 18F‐, 13N‐, and 15O‐Labeling Reactions

“…In addition, Riss et al. reported an improved PPh 3 ‐assisted 18 F‐fluorination of aryliodonium ylides, which showed increased fluorination yields and reaction rates …”

Chemie der Positronenemissionstomographie: Aktuelle Fortschritte bei 11C‐, 18F‐, 13N‐ und 15O‐Markierungsreaktionen

“…Ferner berichteten Riss et al. über eine verbesserte PPh 3 ‐vermittelte 18 F‐Fluorierung von Aryliodoniumyliden, mit erhöhter Ausbeute und Reaktionsgeschwindigkeit …”