<P> In organic chemistry, carbonyl reduction is the organic reduction of any carbonyl group by a reducing agent . </P> <P> Typical carbonyl compounds are ketones, aldehydes, carboxylic acids, esters, and acid halides . Carboxylic acids, esters, and acid halides can be reduced to either aldehydes or a step further to primary alcohols, depending on the strength of the reducing agent; aldehydes and ketones can be reduced respectively to primary and secondary alcohols . In deoxygenation, the alcohol can be further reduced and removed altogether . </P> <P> Metal hydrides based on boron and aluminum are common reducing agents; catalytic hydrogenation is also an important method of reducing carbonyls . Before the discovery of soluble hydride reagents, esters were reduced by the Bouveault--Blanc reduction, employing a mixture of sodium metal in the presence of alcohols . </P>

Preparation of alcohol by reduction of carbonyl compounds