JEE Main · 2019 · Shift-IImediumHALO-115

The major product of the following reaction is:

Haloalkanes & Haloarenes · Class 12 · JEE Main Previous Year Question

Question

The major product of the following reaction is: image

Options
  1. a

    image

  2. b

    image

  3. c

    image

  4. d

    image

Correct Answerc

image

Detailed Solution

Step 1: Identify the substrate

Tertiary carbon with:

  • Cl (leaving group)
  • Ester groups (\ceCOOC2H5\ce{-COOC2H5})

Step 2: Reaction with NaOEt

Sodium ethoxide = Strong base

With tertiary halide → E2 elimination favored over SN2S_N2

Step 3: Apply Zaitsev's rule

E2 elimination removes:

  • Cl (leaving group)
  • β-hydrogen

Forms more substituted alkene (Zaitsev product)

Step 4: Consider ester groups

Ester groups (\ceCOOC2H5\ce{-COOC2H5}) are:

  • Electron-withdrawing (inductive)
  • Can stabilize adjacent negative charge
  • Don't significantly affect elimination regiochemistry

Product: Alkene with ester substituents

Answer: (c)

Key Points:

E2 with polyfunctional molecules:

  • Identify leaving group (Cl)
  • Identify β-hydrogens
  • Apply Zaitsev's rule (unless bulky base)
  • Consider electron-withdrawing groups

Ester effects:

  • Electron-withdrawing by induction
  • Can participate in conjugation if adjacent to C=C
  • α,β-Unsaturated esters are stable (conjugated)

Tertiary halides:

  • Strongly favor elimination over substitution
  • Even with good nucleophiles
  • Steric hindrance blocks SN2S_N2

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The major product of the following reaction is: (JEE Main 2019) | Canvas Classes