Quantification of the Interaction of SmI₂ with Substrates and Ligands

The method developed and introduced here enables for the first time (to the authors' knowledge), a quantitative assessment of the interaction of SmI₂ with substrates prior to the electron transfer stage. As a proof of concept, equilibrium constants for some model substrates including carbonyl compounds and aromatic nuclei are reported here. In addition, the first equilibrium constants with some common ligands were also determined. The equilibrium constants range from approximately 0.07 m^-1 for diisopropyl ketone to 2500 m^-1 for hexamethylphosphoramide (HMPA). It is shown that the data acquired by this method, which is based on the concept of shift reagents, can shed light on the most intimate details of the reaction mechanism, and this method is a useful tool for planning a synthetic process.