Highly hindered 2-(aryl-di-tert-butylsilyl)-N-methyl-imidazoles: a new tool for the aqueous 19F- and 18F-fluorination of biomolecule-based structuresElectronic supplementary information (ESI) available: General experimental procedures and analysis/spectroscopic data (1H NMR, 13C NMR and radio-HPLC chromatograms). See DOI: 10.1039/c8cc01782d

A new class of silicon-based fluoride acceptors with a C-linked heterocycle as the leaving group was synthesized in one step from commercial chemicals, and linked to biomolecules. The resulting conjugates were efficiently 19 F-fluorinated in aqueous mixtures, and switching to 18 F-labelling provided nucleoside- and peptide-based bioconjugates with excellent molar activities suitable for biological applications. Conjugation with a 2-(aryl-di- tert -butylsilyl)- N -methyl-imidazole tag enabled the last-step labelling of biomolecule-based structures by [ 19 F] and [ 18 F]fluoride in aqueous mixtures.