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UPSC Combined Geo-Scientist

Chemist

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

Mains Paper III covers analytical and organic chemistry.

UPSC Combined Geo-Scientist, Mains · 2016 · Mains Paper III

Q11(c). Substituent effects in benzoin condensation

Question

Explain the statement that electron-donating or electron-withdrawing substituents can cause failure or low yields in benzoin condensation.

Answer in brief

The reaction requires both electrophilic aldehyde addition and a sufficiently nucleophilic acyl-anion equivalent; substituents affect these stages differently.

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CoversSubstituent effects in benzoin condensationUmpolung chemistry

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