Advices For Studying Organic Chemistry

2) Since A and B are equivalent resonance structures, the allyl radical should be

much more stable than either, that is, much more stable than a 1° radical ⇒ the

allyl radical is even more stable than a 3° radical.

13.4 THE ALLYL CATION

1. The allyl cation (CH 2 =CHCH 2 +) is an unusually stable carbocation ⇒ it is more
   stable than a 2° carbocation and is almost as stable as a 3° carbocation.

1. The relative order of carbocation stability:

>CC

C

C

>CH 2 CHCH 2 >CC

C

H

>CC

H

H

C C C C CH^2 CH

H

+ + + ++> +

Substituted allylic > 3° > Allyl > 2° > 1° > Vinyl

1. MO description of the allyl cation: