This approach to enolization is based on the cooperative action of a carbonyl-activating hydrogen bonding (thio) urea moiety and an amine base contained within a single catalytic entity to facilitate intracomplex deprotonation.
This allows thioesters over a range of acidity to react efficiently, thereby opening the door to the development of a general mode of enolization-based organocatalysis of monocarboxylic acid derivatives.