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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3o3053

Neopentyl bromide, , is heated in ethanol without added base. Choose the correct statement(s).

  1. AThe reaction is first order in the substrate, because the solvent is used in large excess and the slow step does not need a strong nucleophile.
  2. BDirect SN2 displacement by ethanol is the main pathway and gives mainly the unrearranged ether.
  3. CThe major substitution product is 2-ethoxy-2-methylbutane.
  4. DThe major substitution product is 1-ethoxy-2,2-dimethylpropane.

Answer: A, C

Back-side attack at the neopentyl carbon is blocked by the tert-butyl group, so SN2 is extremely slow (2 and 4 false). Reaction occurs by ionisation accompanied by a methyl shift to give the tertiary cation; the process is first order in substrate and gives 2-ethoxy-2-methylbutane (1 and 3 true).
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