# What product is formed in the Wurtz reaction of 1-bromo-3-chlorocyclobutane?

I want to do Wurtz reaction of 1-bromo-3-chlorocyclobutane:

Wikipedia suggests to do an intramolecular reaction. Instead, I remember reading somewhere that bromine is more reactive and hence we should do an intermolecular reaction, and attach two carbons to where $\ce{Br}$ was attached.

So, what product is formed in the Wurtz reaction of 1-bromo-3-chlorocyclobutane?

• Cyclobutane is not planar, it has butterfly like structure. Intra molecular reaction is more possible Dec 2, 2019 at 4:18

## 1 Answer

Br is a much better leaving group than Cl.First of all presuming that Cyclobutane is stabilized by substitutent groups is important since it wil gradually rearrange itself to buta diene.But since it is a theoretical question hence we can say that it should add to the Br side since Br leaves more efficiently being larger in size than Cl and hence having less efficient orbital overlap with Carbon as well as a large electronic repulsion due to the large number of electrons it has is the reason behind this.And the major product will probably be a bicyclo [1.1.0] butane since it is the kinetic product. so basically your answer-

• I am not sure about this. Chlorine has a higher electron affinity/ electronegativity compared with bromine and should be reduced first. Then you could have an nucleophilic attack at the C-Br bond. This will result in an asymmetric minor product. May 13, 2014 at 6:31