Question

Which of the following is an allylic halide?

• A. 3-bromo-2-methylpropene
• B. 3-bromobut-1-ene
• C. 3-bromopent-2-ene
• D. 4-bromobut-1-ene

Answer 1

Answer: (A), (B)

The correct options are
A 3-bromo-2-methylpropene
B 3-bromobut-1-ene

Allylic halide is a halide atom present on the carbon which is adjacent to the double bonded carbon. For e.g. ${}^{\ast }C-\underset{|}{C}=\underset{|}{C}-$ , here ${}^{\ast }C$ is the allylic carbon.

$A)$ 3-bromo-2-methylpropene: $C{H}_2=\underset{C{H}_3}{\underset{|}{C}}-C{H}_2-Br$

$B)$ 3-bromobut-1-ene:

$C{H}_2=CH-\underset{Br}{\underset{|}{CH}}-C{H}_3$

$C)$ 3-bromopent-2-ene:

$C{H}_3-CH=\underset{Br}{\underset{|}{C}}-C{H}_2-C{H}_3$

$D)$ 4-bromobut-1-ene:

$C{H}_2=CH-C{H}_2-C{H}_2-Br$