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I am trying to understand why the red Br doesn't react? Is it because there can't be a flip of groups? Or steric hindrance?

Thank you!

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Johnathan
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1 Answers1

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Backside attack on the red bromide is not possible. The rest of the norbornyl skeleton completely blocks the trajectory required for $\mathrm{S}_{N}2$ reaction.

Zhe
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  • Thank you for your answer! If possible, I would like to ask you this question: would the reaction if there were no bridge in the middle? Thank you! – Johnathan Dec 17 '16 at 23:40
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    Yes. Because then, it would just be cyclohexane. As long as you could access the conformation where the red bromide group is axial, you could have a productive substitution reaction. – Zhe Dec 18 '16 at 01:23
  • Excellent answer by Zhe. I'd also like to point out that the red Br is on a tertiary carbon anyway - makes SN2 nearly impossible. – electronpusher Dec 18 '16 at 07:16