Sciencemadness Discussion Board

What are some weak-chlorinating agents for chlorinating a phenolic compound?

Sidmadra - 1-4-2019 at 02:09

I have a bi aryl compound, that I want to chlorinate ortho to one of the phenol groups on one ring. It's the only spot available that could react, and the other ring doesn't have any activating constituents. My understanding is that phenols can undergo halogenation without a catalyst, but for chlorination I am unsure which approach to take.

Hypochlorites are probably out of the question due to their strength in chlorinating even relatively unactivated rings. The next best thing that comes to mind is an oxidation using H2O2/AcOh/Ammonium Salt, but I can only find references about that procedure using hydrobromide or iodide salts, so I'm not sure if it would work for chlorination.

Is there something simple I am overlooking? I'm not used to working with phenolic compounds, and am I working on a very small scale (3-5 mmol) so I prefer to use solids I can weigh for accuracy, if possible.

Metacelsus - 1-4-2019 at 03:52

Sulfuryl chloride might work. See here: and here:

Sadly, it's not a solid and it's not very amateur friendly. You could try N-chlorosuccinimide or trichloroisocyanuric acid, but I don't know how selective those would be.

[Edited on 2019-4-1 by Metacelsus]