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Indian Forest Service (Mains)

Chemistry optional

  • 2 papers
  • 200 marks each
  • 3 h per paper

Paper II covers organic chemistry and spectroscopy.

Indian Forest Service (Mains), Chemistry optional · 2025 · Paper II

Q3(a). Stevens rearrangements of two ylides

Question

Give products and mechanisms for the two displayed ammonium/sulfonium salts with base. [structures of the fluorenyl ammonium salt and phenacyl sulfonium salt given in the paper]

Answer in brief

(i) 9-Benzyl-9-(dimethylamino)fluorene; (ii) PhCOCH(CH₂Ph)SMe.

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Topic notes: molecular rearrangements, with every Civil Services, IFoS and Geo-Scientist PYQ →

CoversStevens rearrangementammonium ylidesulfonium ylideradical pair mechanism[1,2]-shift

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