Direct Nucleophilic 18F-Fluorination of Electron Rich Arenes: Present Limits of No-Carrier-Added Reactions

In order to perform nucleophilic reactions of no-carrier-added [18F]fluoride also with arenes of high electron density an electrophilic center must be generated. This can be achieved by electrochemistry, decomposition of aryl-diazo-compounds, and use of aryl-iodonium compounds. Here, some general features and the application of those methods are described.