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JEE Main levelSingle correct optionDifficulty 2 of 3o4183

trans-1-Bromo-2-methylcyclohexane is heated with in ethanol. The major alkene is:

  1. A1-methylcyclohexene
  2. B3-methylcyclohexene
  3. Cmethylenecyclohexane
  4. D2-methylcyclohexyl ethyl ether

Answer: B

The stable chair has Br and both equatorial. E2 needs the diaxial conformer, where on C2 is axial, so the C2-H is equatorial and not anti to Br. Only the axial H on C6 is anti-periplanar, giving the double bond C1=C6, i.e. 3-methylcyclohexene, despite its lower substitution.
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