Skip to content
qorganica.es qorganica.comOrganic Chemistry made transparent Course map Español

SolutionsBimolecular Nucleophilic Substitution

1. Complete the reactions

  1. CH3CH2Br + NaI (acetone) →
  2. CH3I + NaCN →
  3. CH3CH2CH2Cl + NaSCH3 →
  4. CH3Br + NH3 →
  1. CH3CH2I + NaBr
  2. CH3CN + NaI
  3. CH3CH2CH2SCH3 + NaCl
  4. CH3NH3+ Br− (methylammonium bromide)

2. Stereochemistry

What product is obtained from (R)-2-bromobutane with NaCN in DMSO? State its configuration.

(S)-2-Methylbutanenitrile. Cyanide attacks from the side opposite the bromine and the configuration is inverted; since CN takes the place of Br with the same (highest) priority, the descriptor changes from R to S.

3. Stereospecific

Why is the SN2 reaction said to be stereospecific?

Because each stereoisomer of the substrate gives one specific stereoisomer of the product: always with inversion of configuration (Walden inversion).

4. Identify the roles

In the reaction CH3CH2I + CH3O− → CH3CH2OCH3 + I−, identify the substrate, the nucleophile and the leaving group.

Substrate: iodoethane. Nucleophile: the methoxide ion. Leaving group: the iodide ion.

← Back to the exercises