The GATE Grind

GATE 2026 CY – Question 22

Organic Chemistry · Oxidation: Oxidation of alcohols involving metal and non-metal-based (chromium, manganese, DMSO, and hypervalent iodine) reagents. Peracid oxidation of alkenes and carbonyls. Alkenes to diols (manganese and osmium-based reagents), alkenes to carbonyls with bond cleavage (ozonolysis), and alkenes to alcohols/carbonyls without bond cleavage (hydroboration-oxidation). Asymmetric epoxidations (Sharpless and Jacobsen) and Sharpless asymmetric hydroxylation. · 1 mark · Multiple select

The reaction(s) that give(s) meso-1,2-diphenylethane-1,2-diol as the major product is(are)

Cis/trans stilbene undergoing osmium hydroxylation or iodine–silver acetate oxidation.
  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; (D) Option D in the figure

Explanation

Syn hydroxylation of cis-stilbene yields the meso diol. Dry iodine–silver acetate followed by hydrolysis effects anti addition; trans-stilbene therefore gives the same meso product.