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GATE 2023 CY – Question 51

Organic Chemistry · Stereochemistry: Chirality and symmetry of organic molecules with or without chiral centres and determination of their absolute configurations and optical purity. Relative stereochemistry in compounds having more than one stereogenic centre. Homotopic, enantiotopic and diastereotopic atoms, groups and faces. Conformational analysis of acyclic and cyclic compounds. Geometrical isomerism and optical isomerism. Configurational and conformational effects, atropisomerism, and neighbouring group participation on reactivity and selectivity/specificity. Stereoselective and stereospecific synthesis. Enantiomeric excess. · 2 marks · Multiple select

The reaction(s) in which inversion of configuration occur(s) is(are)

Diagram for GATE 2023 CY question 51
  1. Structure A
  2. Structure B
  3. Structure C
  4. Structure D

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Show answer and explanation

Correct answer: (A) Structure A; (B) Structure B

Explanation

Mitsunobu esterification A substitutes the activated alcohol by backside carboxylate attack, inverting its centre. Thermal carbon migration B is stereospecific with the inversion required for the migrating carbon in the allowed sigmatropic process. Hofmann rearrangement C and Baeyer–Villiger migration D retain migrating-group configuration. **Select A, B**.