Abstract
The present critical review outlines the close relationship and mutual interplay between molecular recognition, active site considerations in enzyme catalysis involving organocatalysis via hydrogen bonding. These interconnections are generally not made although; as we demonstrated they are quite apparent as exemplified with pertinent examples in the field of urea organocatalysis. Urea organocatalysis derivatives have been used as efficient Lewis-acidic catalysts due to effective H-bonding, basic catalyst, coupling with metals as catalyst, chiral acid catalysts, urea anions catalysts, coupling with ionic liquids, urea polymer catalysts and immobilization on solid acid and magnetic nanoparticle supports. Consecutively, the discovery and mechanistic elucidation of such reactions are likely to improve the understanding of enzyme active sites.