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Most books I have read stop at this order :
Benzylic > Allylic > Tertiary > secondary > primary
However If I want to compare tertiary, secondary and primary benzylic and Allylic carbocations what will be their stability order?

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closed as unclear what you're asking by bon, M.A.R., jerepierre, Todd Minehardt, orthocresol Nov 30 '15 at 20:27

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    $\begingroup$ Tertiary benzylic carbocations should be stabilised more due the $+M$ effect of three benzylic groups. The same should apply for allylic carbocations. $\endgroup$ – Gokul Apr 28 '15 at 17:06
  • $\begingroup$ Should the answer then be tertiary benzylic>Secondary benzylic>primary benzylic> tertiary Allylic > secondary allylic> primary Allylic > tertiary> primary> secondary $\endgroup$ – novak Apr 28 '15 at 17:08
  • $\begingroup$ Yes, seems correct to me. $\endgroup$ – Gokul Apr 28 '15 at 17:10
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    $\begingroup$ There is no simple general rule for this. The rules you state are also not "absolute". $\endgroup$ – Jori Apr 29 '15 at 16:18
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    $\begingroup$ Can you clarify what you mean by tertiary benzylic etc. Do you mean three phenyl groups (trityl cation) or one phenyl group and two alkyl groups? $\endgroup$ – bon Nov 30 '15 at 15:54
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Yes tertiary allyllic carbocation is more stable than secondary because no. of electrone donating methyl groups are greater than secondary (in tertiary 3 methyl groups while in secondary are 2) so they decrease electrophilicity carbocation but it still it remain electrophillic.

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