Master Organic Chemistry Reaction Guide

Addition of LiAlH4 to aldehydes to give primary alcohols

Description: Addition of lithium aluminum hydride to aldehydes leads to formation of primary alcohols (after addition of acid)

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7 thoughts on “Addition of LiAlH4 to aldehydes to give primary alcohols

  1. Hi,i have a question about the reduction of an aldehyd to a primary alcohol,in the class I learned that it can be done either with adding NaBH4+etoh(weak acid) or with LiAlH4 and than we have to add et2o and not an acid????

    1. Reduction of aldehydes can be performed with NaBH4 or LiAlH4. If ether is mentioned, it acts as a solvent only. The second step is addition of some kind of proton source to give the neutral alcohol. This is sometimes written as H3O+ or NH4Cl.

  2. Hi,
    I just want to know how to get rid of the OH after the addition of LiAlH4, ether?

    im trying to convert butanoic acid to 1-bromobutane. I know I have to first use LiAlH4, ether then H3O+,but how does the ether come into place? after the addition of this, I get OH but i am trying to remove OH, how do i do that?


    1. You’d get 1-butanol and then want to convert that to 1-bromobutane. Well, you could use PBr3 , or concentrated HBr. (my vote is for PBr3). A slightly different way would be to make the mesylate or tosylate and then displace with KBr in a polar aprotic solvent like acetonitrile.

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