[SeriouSyrius]

I had been working for days to get this product. I found multiple ways but they are all not the perfect answer. Just want to know how would you prepare this product from a benzene?

[Dan]

I found multiple ways but they are all not the perfect answer.

Please show what you did, it's a forum rule.

[SeriouSyrius]

I found the shortest method already.

Benzene --Cl2/FeCl3--> Chlorobenzene --HCOCl/AlCl3--> 4-chlorobenzaldehyde ---NaOH-->
4-hydroxybenzaldehyde



A few of my methods I used.

[kriggy]

Im not sure if your 1st method works (the written one). FC acylation doesnt work with formyl chloride as I was told.
You could use KMnO₄ to oxidize the chlortoluene to chlorobenzoinc acid or It should be possible to oxideze CH₃ to CHO with SnO₂

[SeriouSyrius]

My lecturer said it was right so I'm just going to use that. 

[Dan]

FC acylation doesnt work with formyl chloride as I was told.

The problem is that formyl chloride is extremely unstable. It does do F-C acylation, but you can't buy it (as far as I'm aware) - it can be generated in situ with CO and HCl (Gatterman-Koch reaction).

[kriggy]

Oh ok. Thanks for clarifying