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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: miragelife on April 20, 2020, 01:23:54 PM

Title: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: miragelife on April 20, 2020, 01:23:54 PM
Hello!

I am doing a project for school and I wanted to include this reaction into it: the transformation of 1-chloro-2-(dichloromethyl)benzene into 2-chlorobenzaldehyde.
[attached it, and here is direct link to it: https://www.prepchem.com/synthesis-of-4-chlorobenzaldehyde/ ].

What I want to know is what the mechanism behind this reaction is because i can't figure it out myself. Could anybody help me out with this one?
Title: Re: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: miragelife on April 20, 2020, 01:24:51 PM
I forgot to add the reaction conditions. The reactions takes place in an acidic medium - H2SO4 in the link.
Title: Re: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: Babcock_Hall on April 20, 2020, 03:28:24 PM
Would you please give us your thoughts first?
Title: Re: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: miragelife on April 20, 2020, 05:15:09 PM
I would say something like this might happen. What is bothering me in this mechanism is the acidity. So I added H3O+ in the end to neutralize Cl-. But what if water is mostly arleady protonated at the start. That would probably hinder it's nucleophility right? Do halogen bonds affect do reaction? Can halogen ease the nucleophilic attack of a H3O+?
Title: Re: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: Babcock_Hall on April 20, 2020, 09:55:49 PM
Another possibility is that there is a carbocation intermediate.
Title: Re: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: miragelife on April 21, 2020, 03:06:58 AM
Thank you, I tought of that. The benzene does nicely stabilize the carbocation right
Title: Re: What is the mechanism for transforming a dichloro compound into an aldehyde
Post by: Babcock_Hall on April 21, 2020, 08:13:13 AM
Yes, through resonance delocalization.