Aryl Azides as Phosphine-Activated Switches for Small Molecule Function

Engineered small molecule triggers are important tools for the control and investigation of biological processes, in particular protein function. Staudinger reductions of aryl azides to amines through the use of phosphines can trigger an elimination reaction, and thereby activation of a functional molecule, if an appropriately positioned leaving group is present. We conducted detailed investigations of the effect of aryl azide and phosphine structure on both the mechanism and kinetics of these reaction-induced eliminations and identified phosphine/azide pairs that enable complete activation within minutes under physiologically relevant conditions.