Consider the following alkyl halides 1 . ( C H 3 ) 3 C C H 2 B r 2 . C l C H 2 C H = C H 2 3 . C l C H 2 C H…

Consider the following alkyl halides

1. (CH3)3CCH2Br

2. ClCH2CH=CH2

3. ClCH2CH2CH3

4. BrCH2CH2CH3

Arrange these alkyl halides in decreasing order of reactivity in Williamson reaction.
  1. 2 > 1 > 3 > 4
  2. 2 > 1 > 4 > 3
  3. 1 > 2 > 3 > 4
  4. 2 > 4 > 3 > 1

Solution

The Williamson reaction involves nucleophilic substitution of alkoxide ion for halide ion. It is strictly analogous to the preparation of alcohol by treatment of alkyl halide with aqueous hydroxide. Allyl halides undergo nucleophilic substitution at faster rate than aliphatic halides and bromides are more reactive than the corresponding chloride.
Neopentyl-type halides are inert to nucleophilic substitution (SN2) because they show maximum steric hindrance to the approaching nucleophilic.
Here the reactivity order is 2 > 4 > 3 > 1.

Asked in: JEE-TOPICTESTS-CHEMISTRY

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