Varying the Electronics on Isothiourea Catalysts: Basicity, Rate, and Selectivity

Abstract Chiral and achiral substituted isothiourea catalysts were synthesized and employed in model silylation reactions to understand how changing the electronics on the catalyst core affected intermolecular interactions between catalyst intermediates and substrates, ultimately affecting selectivity and rate. Five different chiral catalysts were utilized in a silylation‐based kinetic resolution of 2‐(para substituted)phenylcyclohexanols and the rate of silylation of these same alcohols was investigated with three different achiral catalysts. Linear free energy relationships were examined, highlighting that rate and selectivity were highly dependent on the electronics of the catalyst and the substrate, and that both affected the intermolecular interactions that resulted.