Squaramide Based Organocatalysts in Organic Transformations

Organocatalysis is an emerging and new field towards the direction of asymmetric synthesis and has shown a tremendous growth in 21st century. As the demand for chiral pharmaceuticals and chiral organic molecules is increasing immensely, different types of organocatalysts have been developed and used from time to time. The cinchona alkaloids and amino acid proline were the first organocatalysts used in this area followed by incredible growth in the form of urea/thiourea, DMAP, proline derivatives, squaramides, peptides, etc. The squaramide based organocatalysts are gaining impetus for asymmetric transformations and have shown remarkably good results in diverse type of reactions, wherein they usually act as linkers between two privileged skeletons. Due to its unique structural feature and wide application, squaramide holds a prominent and great potential in asymmetric synthesis. The present mini-review will briefly cover the squaramide based organocatalysts and the examples of organic reactions catalyzed by them.