Cyanhydrins

Cyanohydrins are a class of organic compounds that contain both a nitrile group and a hydroxyl group on the same carbon atom. They are typically formed by the addition of hydrogen cyanide (HCN) to an aldehyde or a ketone. This reaction is an example of nucleophilic addition to a carbonyl group. The cyanide ion acts as the nucleophile, attacking the electrophilic carbon of the carbonyl group. This addition is often catalyzed by a base, which deprotonates HCN to form the more nucleophilic cyanide ion.

The general structure of a cyanohydrin is R1R2C(OH)CN, where R1 and R2 can be hydrogen atoms, alkyl groups, or aryl groups. If one of the R groups is a hydrogen atom, the starting material is an aldehyde, and the resulting cyanohydrin will have a chiral center if the other R group is not also a hydrogen. If both R groups are alkyl or aryl, the starting material is a ketone, and the resulting cyanohydrin will also possess a chiral center. The formation of cyanohydrins is reversible, and the equilibrium can be shifted depending on the reaction conditions.

Cyanohydrins are important intermediates in organic synthesis. They can be hydrolyzed to form alpha-hydroxy acids, which are valuable building blocks for various pharmaceuticals and natural products. They can also be reduced to form beta-amino alcohols. A classic example of cyanohydrin chemistry is the synthesis of mandelic acid from benzaldehyde.