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GATE 2022 CY – Question 11

Organic Chemistry · Reduction: Catalytic homogeneous and heterogeneous hydrogenation. Metal based reductions using Li/Na in liquid ammonia, magnesium, zinc, titanium, and samarium. Hydride transfer reagents: NaBH4, L-selectride, K-selectride, Luche reduction, LiAlH4 and DIBAL-H. · 1 mark · Multiple choice

The major product M formed in the following reaction is

Diagram for GATE 2022 CY question 11
  1. Diagram A
  2. Diagram B
  3. Diagram C
  4. Diagram D

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Correct answer: (B) Diagram B

Explanation

Oxidation of hydrazine produces diimide, which transfers two hydrogens syn across an alkene. The cis double bond is reduced preferentially because the cyclic transition geometry is more accessible than for the trans alkene. One equivalent leaves the trans double bond intact, giving **B** rather than fully saturated C.