Light-activated atom swapping

Another atom-swapping reaction has entered the ring. Yoonsu Park and his team at the Korea Advanced Institute of Science and Technology have devised a light-driven reaction that replaces the oxygen atom in furan rings with a nitrogen atom ( Science 2024, DOI: 10.1126/science.adq6245 ). Unlike other recent atom-swapping examples, it is catalytic and designed for five-membered rather than six-membered aromatic rings. The ability to alter complex molecules by a single atom at a time would be incredibly useful for medicinal chemistry. It would enable researchers to, for example, test the influence of different heteroatoms on a drug lead’s properties without having to synthesize each variant from scratch. This sort of pencil-and-eraser chemistry, as Park calls it, looks simple on paper but it’s far from easy to perform. It requires busting up an extremely stable aromatic system, switching around the atoms, and then stitching the molecule back together. “There is a