Reversible modulation of the activity of thiourea catalysts with anions: a simple approach to switchable asymmetric catalysis

Leveraging the anion binding properties of thioureas, we show that the activity of known well-performing chiral catalysts can be reduced by coordinating anions (e.g. chloride) and restored by anion metatheses. Three benchmark enantioselective transformations were successfully studied, demonstrating the reversibility of the activation/deactivation processes.