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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ap184

1-Methylcyclopentene is subjected to hydroboration with /THF followed by /. Which statements are correct?

  1. AThe OH group is introduced on the ring carbon that does not carry the methyl group
  2. BH and OH are added to the same face of the double bond (syn addition)
  3. CThe reaction goes through a free carbocation, so 1-methylcyclopentan-1-ol is the major product
  4. DThe major product is trans-2-methylcyclopentan-1-ol (as a racemic mixture)

Answer: A, B, D

Hydroboration is concerted, anti-Markovnikov and syn, with boron on the less substituted carbon, so OH ends up on C-2. H on C-1 and OH on C-2 are cis, so the methyl and OH are trans. No carbocation is involved, so statement C is wrong.
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