For Cu-mediated aromatic 18 F-fluorination of Bpin esters, it is known that pronounced losses of radioactivity occur during the work-up of the reaction. In addition, nonradioactive by-products due to protodeboronation and oxidation (formation of the phenol) , increase during the 18 F labeling reaction, which typically takes 20 min for most Cu-mediated 18 F-fluorinations reported to date . We have addressed this issue by proposing boronic acid anhydrides, i.e. boroxines, as alternative labeling precursors, as our experiments with simple aromatic boroxines revealed accelerated 18 Ffluorination . In the present work, we were able to show that the use of boroxine 4c