# Why doesn't the protonated propyne rearrange? [closed]

In the reaction of propyne with $$\ce{HBr}$$ this cation (prop-1-en-2-ylium) was mentioned by my teacher: $$\ce{H3C-\overset{+}{C}=CH2}$$

He told me that the carbocation will not rearrange as it will have no change in stability. When I pointed out that the carbocation could shift away from the double bond, as this will provide resonance stability to the carbocation, he just got silent for two minutes and then said it does not rearrange.

Can someone please explain why it cannot rearrange?

• This seems quite relevant: Why are vinylic and arylic carbocations highly unstable? Sep 16 at 21:11
• You changed the structure. Is this what you really mean? Is it a triple or double bond? Sep 16 at 21:20
• This link may be helpful. chemistry.stackexchange.com/questions/2774/… @Martin Sep 17 at 1:46
• You can refer the book David Klein's Organic Chemistry. It is discussed in there Sep 18 at 17:03
• Apologies, I have put the wedding structure. Sep 18 at 21:14