Photocatalyzed ¹⁸F-Fluorination: A Streamlined Radiolabeling Approach for Rapid Adoption and Automation

Area of Science:

• Radiochemistry
• Organic Chemistry
• Medical Imaging

Background:

• Developing efficient methods for incorporating fluorine-18 (¹⁸F) into organic molecules is crucial for positron emission tomography (PET) imaging.
• Traditional ¹⁸F-labeling often requires harsh conditions, such as high temperatures and azeotropic drying, limiting substrate scope and complicating automation.

Purpose of the Study:

• To establish a simplified and rapid photoredox-mediated system for aryl ¹⁸F-fluorination.
• To enable ¹⁸F-labeling of electron-neutral and electron-rich arenes via ¹⁹F-¹⁸F exchange or deoxyfluorination without azeotropic drying.

Main Methods:

• Utilized a photoredox-mediated reaction system.
• Employed a HPO₄²⁻ preconditioned anion exchange resin for efficient fluoride-18 (¹⁸F) incorporation.
• Performed labeling via ¹⁹F-¹⁸F exchange and/or deoxyfluorination.

Main Results:

• Achieved rapid aryl ¹⁸F-fluorination of functionalized arenes.
• The reaction proceeded efficiently without the need for azeotropic drying.
• Demonstrated successful radiosynthesis on an automated module using the entire eluted ¹⁸F⁻.

Conclusions:

• The developed simplified photoredox system offers a rapid and efficient method for ¹⁸F-labeling.
• The system's compatibility with automated radiosynthesis and use of readily available reagents facilitates broad adoption.
• This technique holds promise for advancing PET tracer development and production.