Modern Carbon-Fluorine Bond Forming Reactions for Aryl Fluoride Synthesis

The synthesis of functionalized aryl fluorides by C-F bond formation remains a challenging and important problem. Metal-catalyzed nucleophilic arene fluorination uses inexpensive fluoride salts and aryl (pseudo)- halide substrates, but a key remaining challenge is the basicity of fluoride under the reaction conditions, which can lead to undesired side reactions. Selective C-H functionalization of arenes, without the use of coordinating directing groups, is an area of active research, and a selective C-H fluorination of complex arene substrates would be a powerful advance for the field of fluorination. As an additional conceptual challenge to consider when targeting arene C-H fluorination, the fluorinated product is typically difficult to separate from unreacted starting material by standard chromatographic methods.