Squaramide catalysis

The scope of these small-molecule H-bond donors termed squaramide organocatalysis covers both non-stereoselective and stereoselective applications.

For enantioselective squaramide catalysis, chirality is induced via the tertiary amine group.

[1] H-bond accepting substrates include carbonyl compounds imines, Michael acceptors, and epoxides.

The nucleophile can be nitroalkanes, enolates, and even phenols (resulting in electrophilic aromatic substitution).

[1] Squaramide catalysts are developed in 2008 by Jeremiah P. Malerich, Koji Hagihara, and Viresh H.

General structure of squaramide organocatalyst
Interaction between squaramide catalyst and substrate exemplified by the conjugate addition of an enolate to an unsaturated ketone