Molecular editing made its mark

When chemists construct drug candidates, there's an aspect of the design process that's kind of like grappling in the dark . Would the molecule fit its target better if it had a five-membered ring instead of a six-membered ring? What if there were a nitrogen instead of a carbon at a particular spot? Such subtle tweaks are easy to make on paper but often require chemists to build the redesigned molecule from scratch. Molecular editing—reactions which selectively insert, delete, or exchange an atom in a complex molecule—aims to change that. Molecular editing is having a moment. In 2021, chemists published several high-profile papers that feature molecular editing. Chemists in Mark D. Levin's lab at the University of Chicago developed a reaction that could snip the nitrogen out of a secondary amine, allowing chemists to make, for example, cyclobutanes from pyrrolidines ( Nature 2021, DOI: 10.1038/s41586-021-03448-9 ). Levin's lab also reported