[arvind1990]

How do you convert acetaldehyde to

a)Butan-2-one b)Butan-1,3-diol c)But-2-enal d)Butanol e)Butanoic acid

f)But-2-enoic acid.

write the structures of the expected products of Aldol condensation:

a)2-methtylpentanal b)cyclohexanone c)1-phenylacetaldehyde d)phenylpropanone

[Dan]

Well, the aldol condensations are straightforeward. Look up 'aldol condensation' in a book.

What are your ideas so far on the synthesis of the first ones? Show some of your own input.

[arvind1990]

I don not have any idea in the synthesis of the first ones.
I think for the synthesis of( a),we can use cross aldol condensation
ie.,CH3CH0 + CH3COCH3.
I donot have any ider other than this.

[arvind1990]

Can anyone help me with those conversions(mentioned above).

[Dan]

I don not have any idea in the synthesis of the first ones.
I think for the synthesis of( a),we can use cross aldol condensation
ie.,CH3CH0 + CH3COCH3.
I donot have any ider other than this.

yes, that aldol reaction following dehydration will give CH₃COCH=CH₂, you can then use catalytic hydrogenation to hydrogenate the C=C

b) same reaction, but do not dehydrate the aldol product (use very dilute base), and reduce the carbonyl with eg. LiAlH₄

c) This one is just an aldol self-condensation, followed by dehydration

d) is c) followed by hydrogenation of the C=C, and reduction of the carbonyl.

e) is c) followed by hyrogenation of the C=C, and then oxidation of the carbonyl

f) is e) but without the hydrogenation step

[arvind1990]

Hi,

Thank You for your reply. Can you say how to dehydrate the aldol formed between the reaction od CH3CHO and CH3COCH3 i.e., how you got the product CH3COCH=CH2

[Dan]

Sorry, I have made a mistake,

For a) EtLi , then oxidise to ketone. This might be a bit dodgy due to the basicity of the EtLi.

for b) Aldol self condensation, followed by reduction of the carbonyl