Saved Bookmarks
| 1. |
Predict the order of reacitivity of the following compounds in S_(N)1 and S_(N)2 reactions: (2) C_(6)H_(5)CH_(2)Br C_(6)H_(5)(CH_3)Br, C_(6)H_(5)C(CH_3)(C_(6)H_5)Br. |
|
Answer» SOLUTION :The order of stabilty of the CARBOCATIONS derived from the given alkyl broamides is : `C_(6)H_(5)overset(color(red)(o+))(C)H_(2) < C_(6)H_(5)overset(color(red)(o+))(C)H(CH_3) < C_(6)H_(5)overset(color(red)(o+))(C)H(C_(6)H_5)< C_(6)H_(5)overset(color(red)(o+))(C)(CH_3)(C_(6)H_(5))`. so in `S_(N)1` pathway reactivity is `C_(6)H_(5)CH_(2)Br < C_(6)H_(5)CH(CH_(3))Br < C_(6)H_(5)CH(C_(6)H_(5))Br < C_(6)H_(5)C(CH_3)(C_(6)H_(5))Br`. In `S_(N)1` pathway, reactivity of the alkly HALIDES decreases as the steric hindrance around the electrophilic carbon (i.e. `alpha`-carbon) incrases. Since `C_(6)H_(5)` group is larger than `CH_(3)` group, the reactivity follows the sequence: `C_(6)H_(5)C(CH_3)(C_(6)H_(5))Br < C_(6)H_(5)CH(C_(6)H_(5))Br < C_(6)H_(5)CH(CH_3)Br < C_(6)H_(5)CH_(2)Br`. |
|