Reductive samarium (electro)catalysis enabled by SmIII-alkoxide protonolysis

Editor’s summarySamarium diiodide is widely used as a reductant in reactions of carbonyl compounds. However, it has poor solubility and must generally be used in excess quantities. Attempts to use this reductant catalytically have been hindered by its tight binding to oxygen during reactions. Boyd et al. now report that a well-chosen acid can help cleave the samarium-oxygen bond and induce turnover with electrons provided electrochemically or by metallic zinc. Lactone formation from ketone coupling with acrylates showcased the catalysis. —Jake S. Yeston