JEE Main · 2021 · Shift-ImediumHC-078

For the given reaction: What is A (major product)?

Hydrocarbons · Class 11 · JEE Main Previous Year Question

Question

For the given reaction: image What is A (major product)?

Options
  1. a

    \ceCH3CH2CH2NH2\ce{CH3CH2CH2NH2}

  2. b

    image

  3. c

    image

  4. d

    image

Correct Answerb

image

Detailed Solution

Step 1: NaNH2 -- Dehydrohalogenation \ceNaNH2\ce{NaNH2} is a strong base. It eliminates HBr:

Step 2: Red Hot Iron Tube at 873 K -- Trimerization

3\ceCH3CCCH3873KFe1,3,5-trimethylbenzene (mesitylene)3\,\ce{CH3-C≡C-CH3} \xrightarrow[873K]{Fe} \text{1,3,5-trimethylbenzene (mesitylene)} image Trimerization of 2-butyne over red hot Fe tube gives 1,3,5-trimethylbenzene.

Key Points:

  • NaNH2: strong base for dehydrohalogenation of vinyl/propargyl halides
  • Fe tube at 873 K: cyclotrimerization of alkynes to aromatic compounds
  • 2-butyne trimerizes to 1,3,5-trimethylbenzene (mesitylene)

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For the given reaction: What is A (major product)? (JEE Main 2021) | Canvas Classes