Question

The correct reactivity order of following C=C / C⁰C bonds towards $\mathrm { Br } ^ { \oplus }$ is :

• A. 4 > 3 > 2 > 1
• B. 3 > 2 > 1 > 4
• C. 1 > 3 > 4 > 2
• D. 1 > 3 > 2 > 4

Answer 1

Answer: (D)

1 > 3 > 2 > 4

Answer 2

c=c at position 1 is more reactive towards electrophile$\mathrm { Br } ^ { \oplus }$ as this is adjacent to o atom to provide +m effect. c=c at position 3 is more substituted as compared to c=c at position 2. alkyne is less reactive towards $\mathrm { Br } ^ { \oplus }$ as compared to alkene.