Give the action of the Clemmensen reduction on 2-butenal?
The Clemmensen Reduction involves adding
The principal action of the Clemmensen Reduction is to reduce a
So, using it on 2-butenal is supposed to turn it into 2-butene.
But when you have
That's why if you wanted to remove the carbonyl oxygen, you should do a similar reduction in basic media, and the Wolff-Kischner reduction qualifies.
The basic counterpart to the acidic Clemmensen reduction is the Wolff-Kishner reduction, which is run in base. It aims to accomplish the same thing, but in different, sometimes more favorable conditions.
The general reactants are hydrazine (
WOLFF-KISHNER VS. CLEMMENSEN
The main benefit of the Wolff-Kishner reduction is that because it's in base, it wouldn't accidentally protonate a hydroxyl group or double bond in the reactant and allow side reactions to occur for acid-sensitive reagents.
Confer with a reaction involving a hydroxyaldehyde reactant (Organic Chemistry, Bruice, Ch. 15.18), and you would see the following conundrum is resolved by choosing one reduction method over the other: