Enhanced Photocatalytic Alkylation using Mg(SPh) ₂ : The Role of Lewis Acidity in Catalyst Activity

Abstract The role of Mg(SPh) 2 on photocatalytic alkylation of an active methylene with a nonactivated alkene was investigated. Kinetic studies indicate that one‐electron oxidation of a Mg enolate is the rate‐determining step. ESR experiments suggest an interaction between Lewis acidic metals and a radical anion species of 4CzIPN. These results suggest that the higher Lewis acidity of Mg(SPh) 2 stabilizes the 4CzIPN radical anion species to enhance its relative abundance and might influence both the one‐electron oxidation step and the radical addition step in the catalytic cycle, leading to enhanced reaction efficiency.