Cinnamaldehyde from cinnamic acid

[deep838]

Can somebody please tell me how to convert cinnamic acid to cinnamaldehyde? I was planning to first make it into the alcohol and then use PCC, but then wondered that reducing the acid might also reduce the α β unsaturated carbons too. Is there any reagent that would do the trick without causing any further troubles?

 

[AGNuke]

I don't think if you'll use a mild reducing agent, it will disturb unsaturated atoms.

 

[deep838]

I don't think if you'll use a mild reducing agent, it will disturb unsaturated atoms.

So will NaBH₄ work? Or Lindlar's? Or Pd with BaSO₄?

 

[AGNuke]

If you want to use Lindlar, do it so via Rosenmund reduction. I leave the work up to you, now you have got the hint.

 

[deep838]

If you want to use Lindlar, do it so via Rosenmund reduction. I leave the work up to you, now you have got the hint.

Thanks.

 

[chemisttree]

I would go with lithium tri(tertbutoxy)aluminum hydride under these conditions.

Any time you use Pd reagents with hydrogen you risk some cross reactivity with olefins.