Rapid Synthesis of Aryl Fluorides in Continuous Flow through the Balz-Schiemann Reaction

The Balz–Schiemann reaction remains a highly utilized means for preparing aryl fluorides from anilines. However, the limitations associated with handling aryl diazonium salts often hinder both the substrate scope and scalability of this reaction. To address this, a new continuous flow protocol was developed that eliminates the need to isolate the aryl diazonium salts. The new process has enabled the fluorination of an array of aryl and heteroaryl amines. Go with the flow: A new continuous flow process for the Balz–Schiemann reaction has been developed. This process obviates the need to isolate potentially hazardous aryl diazonium salts. The short residence and collection times of the process enable the rapid preparation of aryl fluorides from anilines. This process tolerates a broad array of functional groups as well as both aryl and heteroaryl amines.