Which of the following are the starting materials for the Grignard synthesis of tertiary butanol?
Correct answer: A. CH3MgBr + CH3COCH3
- A. CH3MgBr + CH3COCH3
- B. CH3CH2MgBr + CH3COCH3
- C. CH3MgBr + CHCH(OH)CH3
- D. CH3MgBr + (CH3)3CH
Explanation
Tertiary alcohols are prepared by the reaction of a Grignard reagent with a ketone followed by acid hydrolysis. CH3MgBr + CH3COCH3 → (CH3)3COMgBr → (CH3)3C−OH The product is 2-methyl-2-propanol, also known as tert-butyl alcohol. The Grignard reagent acts as a nucleophile, attacking the carbonyl carbon of the ketone and forming a new carbon-carbon bond, resulting in the addition of the CH3 group from the Grignard reagent to the carbonyl carbon of acetone. The oxygen in the carbonyl group becomes protonated, leading to the formation of the alcohol functional group.
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About Alcohols and Phenols
Alcohols are classified as primary, secondary or tertiary and studied through their hydrogen bonding, acidity, oxidation and reactions with active metals, acids and halogenating agents. Phenols require separate treatment because the hydroxyl group is attached to an aromatic ring, making their acidity and electrophilic substitution different from ordinary alcohols.
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