What’s she building in there?
Published: Sept 9
UNLIKE MEDIEVAL ALCHEMISTS, who only dreamt of turning lead to gold, modern chemists are experts at reshaping matter. They can produce many molecules, but the process is often wasteful and time consuming. On the other hand, Mother Nature is much more efficient at the task, proving that chemists still have a lot to learn.
Biological processes use enzymes to create specific chemical reactions with little waste and extreme precision. When compounds react to form new chemicals, they must overcome an interaction barrier keeping them separate substances. Enzymes are the tools that these systems use to lower interaction barriers so that a reaction can occur, and new compounds can be created. Enzymes accomplish this by temporarily tethering the reactants together and orienting them so that they approach each other in the best possible way, rather than just randomly reacting.
Melissa Macdonald is a PhD candidate in André M. Beauchemin’s lab at the U of O, who knows that if chemists can learn to control and create their own enzymes, many reactions could be recreated more efficiently. In Macdonald’s eyes, chemistry can be an elegant art and not just a series of random reactions.
One reaction in particular stands out for Macdonald: Worthless alkynes can become valuable amines by adding a nitrogen-hydrogen bond. Since amines are a common active ingredient in pharmaceuticals, it is shocking that this seemingly simple transformation is so difficult to reproduce. The usual process involves heating the reactants to extremely high temperatures and using metallic catalysts to lower the interaction barrier. It’s exactly the sort of problem that requires a more elegant, artistic strategy.
By designing an organic catalyst that uses the same tethering method as enzymes, Macdonald tackled this notoriously difficult transformation. The tethering molecule directed the approach of the reactants so intelligently that the interaction barrier was reduced and the reaction could occur at room temperature without the help of toxic metal catalysts.