MolSynapsequestion bank
MolSynapse / Question bank / Organic Reaction Mechanisms II: Electrophilic and Radical Reactions / Electrophilic addition to alkenes and Markovnikov rule
JEE Advanced levelSingle correct optionDifficulty 3 of 3o2036

3,3-Dimethylbut-1-ene is converted into an alcohol by three methods: (i) dilute /water; (ii) , then ; (iii) , then . The major alcohols from (i), (ii), (iii), respectively, are

  1. A2,3-dimethylbutan-2-ol; 3,3-dimethylbutan-2-ol; 3,3-dimethylbutan-1-ol
  2. B3,3-dimethylbutan-2-ol; 2,3-dimethylbutan-2-ol; 3,3-dimethylbutan-1-ol
  3. C3,3-dimethylbutan-2-ol; 3,3-dimethylbutan-1-ol; 2,3-dimethylbutan-2-ol
  4. D3,3-dimethylbutan-1-ol; 3,3-dimethylbutan-2-ol; 2,3-dimethylbutan-2-ol

Answer: A

(i) A free secondary cation forms and undergoes a methyl shift, giving 2,3-dimethylbutan-2-ol. (ii) A mercurinium ion prevents rearrangement, giving the Markovnikov alcohol 3,3-dimethylbutan-2-ol. (iii) Hydroboration is anti-Markovnikov, giving 3,3-dimethylbutan-1-ol.
Practice Organic Reaction Mechanisms II: Electrophilic and Radical Reactions More on Electrophilic addition to alkenes and Markovnikov rule

More questions on Electrophilic addition to alkenes and Markovnikov rule