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GATE 2024 CY – Question 24

Organic Chemistry · Types of Reactions: Nucleophilic and electrophilic substitution reactions (both aromatic and aliphatic). Addition reactions to carbon-carbon and carbon-heteroatom (N and O) multiple bonds. Elimination reactions. Reactive intermediates – carbocation, carbanion, carbenes, nitrenes, arynes and free radicals. Molecular rearrangements. Barton decarboxylation and Barton-McCombie reaction, Hunsdiecker reaction. · 1 mark · Multiple select

The reaction(s) that yield(s) X as the major product is (are)

Target methyl cinnamate and four possible synthetic reactions.
  1. Option A in the figure
  2. Option B in the figure
  3. Option C in the figure
  4. Option D in the figure

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Show answer and explanation

Correct answer: (A) Option A in the figure; (B) Option B in the figure

Explanation

The alpha-halo ketone and alpha-halo aldehyde both undergo Favorskii-type rearrangement in methoxide to methyl phenylacetate. DIBAL reduces an ester rather than forming this product; Lindlar reduction stops at a cis alkene.