What is the product of the reaction of 2-methyl-but-1,3-diene with HBr?


What I understand is that carbon (2) will get a positive charge after protonation.

But after this, which should be the major product?

  • 2-bromo-2-methyl-but-3-ene - because in this case the carbocation would be stable because of being tertiary, but the double bond would have less number of hyperconjugated structures and will be less stable


  • 1-bromo-3-methyl-2-butene - as the carbocation would be less stable because it would be primary but the double bond would be much more stable because of 8 $\alpha$ hydrogen available


  • $\begingroup$ @Chakravarthy Kalyan Could you please tell me why you rolled back the edit I made? $\endgroup$ – Martin - マーチン Jul 2 '19 at 17:01
  • $\begingroup$ @Martin there were two question marks when i saw and i changed that to single question .That is all. $\endgroup$ – Chakravarthy Kalyan Jul 2 '19 at 17:11
  • $\begingroup$ @ChakravarthyKalyan Hmm, okay. The system should not have let you do that. $\endgroup$ – Martin - マーチン Jul 2 '19 at 17:47
  • $\begingroup$ @Martin-マーチン How do you get the image to show ?? $\endgroup$ – RandomAspirant Jul 2 '19 at 17:47
  • $\begingroup$ @DivMit Upload them, see chemistry.stackexchange.com/help/formatting $\endgroup$ – Martin - マーチン Jul 2 '19 at 17:48

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