A surprisingly complex epimerization

Network control theory can describe the photochemical isomerization of glucose to allose. This transformation, in which the hydroxy group on a single carbon flips from one stereochemical configuration to the other, seems like a simple epimerization, but the reaction is quite complicated. The chemists who did the work hope others will also use network control theory to better understand chemical transformations ( Science 2024, DOI: 10.1126/science.adp2447 ). In 2020, Massachusetts Institute of Technology chemistry professor Alison E. Wendlandt reported a reaction that converts the common sugar glucose into the rare sugar allose. Her team tried conventional approaches, like density functional theory and kinetic experiments, to understand why the reaction was selective only for one hydroxy group and didn’t epimerize the hydroxy groups on adjacent carbons. But they failed. So Wendlandt and coworkers teamed up with Merck & Co.’s Eugene E. Kwan to get a better handle on what was happening.