Iminium Catalysis inside a Self-Assembled Supramolecular Capsule: Modulation of Enantiomeric Excess

The noncovalent combination of a supramolecular host with iminium organocatalysis is described. Due to cation-pi interactions the reactive iminium species is held inside the host and reacts in this confined environment. The products formed differ up to 92% ee from the control experiments without added host. A model rationalizing the observed difference is presented.