Overview of Reduction Reactions

Overview of Reduction Reactions

A number of reducing agents are available to reduce various types of functional groups. Proper choice of reducing agent allows selective reduction of some functional groups even when other types of reducible groups are present.

Reducing Agent Reactions

LiAlH₄
Aldehydes -> 1^o alcohol
Ketones -> 2^o alcohol
Carboxylic Acid -> 1^o alcohol
Esters -> Alcohols (mixture)
Nitriles -> Amines
Azides -> Amines
Avoid NO₂ Groups

NaBH₄
Aldehydes -> 1^o alcohol
Ketones -> 2^o alcohol
Avoid NO₂ Groups

BH₃/THF

Alkenes, Alkynes -> Hydroboranes
Carboxylic Acid -> 1^o alcohol

H₂/catalyst
(Pt, Pd, Ni...)
NO₂ -> Amines
Alkenes, Alkynes -> alkanes
Aldehydes -> 1^o alcohol
Ketones -> 2^o alcohol

Reducing Agent	Reactions
LiAlH₄	Aldehydes -> 1^o alcohol Ketones -> 2^o alcohol Carboxylic Acid -> 1^o alcohol Esters -> Alcohols (mixture) Nitriles -> Amines Azides -> Amines Avoid NO₂ Groups
NaBH₄	Aldehydes -> 1^o alcohol Ketones -> 2^o alcohol Avoid NO₂ Groups
BH₃/THF	Alkenes, Alkynes -> Hydroboranes Carboxylic Acid -> 1^o alcohol
H₂/catalyst (Pt, Pd, Ni...)	NO₂ -> Amines Alkenes, Alkynes -> alkanes Aldehydes -> 1^o alcohol Ketones -> 2^o alcohol

A sample of the selectivity that can be obtained with these reagents is shown in the following figure.

Last modified 3/31/97

Abby Parrill
Department of Chemistry
Michigan State University

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