Abnormal chemical product in a reaction starting with bromination using ultraviolet light

  • #1
249
24
Homework Statement:
Find the product of the following reaction
Question pic in My attempt section
Relevant Equations:
None
IMG-20200412-WA0036.jpeg


So what I did was-:
The first step is bromination using ultraviolet light which proceeds via formation of free radical.Here free radical on phenyl ring attached carbon will be more stable due to resonance and 1 bromo 1 phenyl ethane will be formed.
In the second step,Bromine will leave as it's a good leaving group and CN- will come in place of bromine.So,according to me the final product would be 1 cyano 1 phenyl ethane.But the answer was given as d).Help.
 

Answers and Replies

  • #2
249
24
I think there is misprint in answer key.In place of one CN CH3 shoukd be there.Am i right?
 
  • #3
chemisttree
Science Advisor
Homework Helper
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Homework Statement:: Find the product of the following reaction
Question pic in My attempt section
Relevant Equations:: None

View attachment 260538

So what I did was-:
The first step is bromination using ultraviolet light which proceeds via formation of free radical.1) Here free radical on phenyl ring attached carbon will be more stable due to resonance and 2) 1 bromo 1 phenyl ethane will be formed.
In the second step,Bromine will leave as it's a good leaving group and CN- will come in place of bromine.So,according to me the final product would be 1 cyano 1 phenyl ethane.But the 3) answer was given as d).Help.
1). the phenyl carbon or the carbon alpha to the aromatic ring produces the most stable radical intermediate.
2) correct.
3) you were correct and 4) (not “d”) is the wrong structure. None of the printed answers are correct unless you assume that 4) is a misprint.
 
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