IIT JEE Revision Carbohydrates - Reduction

Reaction type: Nucleophilic Addition

The C=O groups in open chain forms of carbohydrates can be reduced to alcohols by sodium borohydride, NaBH4, or catalytic hydrogenation (H2, Ni, EtOH/H2O).

The products are known as "alditols"

LiAlH4 is usually not suitable because of its incompatibility with the polar solvents.

Aldehydes, i.e. aldoses, are reduced to primary alcohols.

Ketones, i.e. ketoses, are reduced to secondary alcohols.