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Mike Webster

Why is 1-bromotriptycene inert to nucleophilic substitution?

Debopam Bose   Follow

Sn1 reaction proceed through carbocation intermediate which has planar structure. The structure of 1-bromo triptycene is cage like structure so the bridgehead carbon cannot assume planarity , hence,the formation of a carbocation at the bridgehead position does not take place. Consequently 1-bromotriptycene is inert to sn1reaction.

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Gregory Bloom-Salm  Follow
It would be better if you make your answer more interesting by describing elaborately or adding some images. You could also mark some important sentences as bold, so that it becomes catchy.More
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Brian Smyth  Follow

nucleophillic substitution

Bredt's rule is a consequence of the fact that having a double bond on a bridgehead or carbocation is not stable for small rings (fewer than eight atoms) due to a combination of ring strain, and angle strain (nonplanar alkene).Since SN1 reaction involves carbocation intermediate, and such intermediate is not possible here, hence SN1 IS RULED OUT.SN2, reaction involves a backside attack from the leaving group.Due to stearic hinderence to the backside attack, such a reaction is also not possible.Totally nucleophilic substitution is not possible.

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