Chemistry, asked by CHETANbera7929, 1 year ago

Reduction of diferent type of aldehydes method

Answers

Answered by Gill16648556
2
 
Reactions usually in Et2O or THF followed by H3O+ work-ups

Reaction type:  Nucleophilic Addition

Summary

Aldehydes and ketones are most readily reduced with hydride reagentsThe reducing agents LiAlH4 and NaBH4 act as a source of 4 x H- (hydride ion)Overall 2 H atoms are added across the C=Oto give H-C-O-HHydride reacts with the carbonyl group, C=O, in aldehydes or ketones to give alcohols.The substituents on the carbonyl dictate the nature of the product alcohol.Reduction of  methanal (formaldehyde) gives methanol.Reduction of other aldehydes gives primaryalcohols.Reduction of ketones gives secondaryalcohols.The acidic work-up converts an intermediate metal alkoxide salt into the desired alcohol via a simple acid base reaction. Nucleophilic addition OF LiAlH4 TO AN ALDEHYDEStep 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 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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