Inverse Kinetic Isotope Effect in Singlet-to-Triplet Intersystem Crossing Contributes to Greater Robustness of Deuterated Organocatalyst

Abstract Precisely defined deuterium labeling of simplified Maruoka Catalyst® markedly increases its robustness under basic conditions, but the reason for this has remained unclear. Based on MC_DFT calculations, we find that an inverse kinetic isotope effect in singlet-to-triplet intersystem crossing contributes to the greater robustness of the deuterated catalyst.