Return to Contents  Chapter 17: Aldehydes and Ketones. Nucleophilic Addition to C=O  Ch 17 contents

Hydride Reductions of Aldehydes and Ketones
(review of Chapter 15)

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 in principle 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.

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