Return to Contents Chapter 15: Alcohols, Diols and Thiols Ch 15 contents

Reductions of Aldehydes and Ketones

reduction of aldehydes and ketones using LiAlH4 or NaBH4
Reactions usually in Et2O or THF followed by H3O+ work-ups

Reaction type:  Nucleophilic Addition

Summary

Related Reactions
NUCLEOPHILIC ADDITION OF LiAlH4 TO AN ALDEHYDE
Step 1:
The nucleophilic H in the hydride reagent adds to the electrophilic C in the polar carbonyl group in the aldehyde, electrons from the C=O move to the O creating an intermediate metal alkoxide complex. 
(note that all 4 of the H atoms can react)
reduction of an aldehyde using hydride
Step 2:
This is the  work-up step, a simple acid/base reaction. Protonation of the alkoxide oxygen creates the primary alcohol product from the intermediate complex. 


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organic chemistry © Dr. Ian Hunt, Department of Chemistry University of Calgary