Organocatalysed Cyanations of Carbonyl Compounds

One of the most important carbon-carbon bond forming reactions in organic synthesis is the cyanation of carbonyl compounds. The resulting cyanohydrins are key building blocks for many other important compounds, namely, α- hydroxy acids, α-hydroxy ketones, primary and secondary α-hydroxy amines, α-hydroxy esters and α-amino acids, which are essential in areas such as fine chemistry, agrochemicals and pharmaceuticals. Cyanohydrin synthesis can be catalyzed by enzymes, metal complexes, inorganic and organic componds. The initial synthetic methods have been extensively explored however the organocatalyzed reaction has been referred to in more limited extent. In this paper we will review the cyanation of aldehydes and ketones in the presence of organocatalysts, addressing both the formation of racemic and nonracemic cyanohydrins.