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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 · 2020 · Mains Paper III

Q10(b). Bulky substituents and diene conformation

Question

Compare 2,3-di-tert-butylbuta-1,3-diene and 1,3-di-tert-butylbuta-1,3-diene as Diels–Alder dienes.

Answer in brief

The 2,3 isomer is much more favourably disposed to the reactive s-cis geometry than the 1,3 isomer.

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The full model answer

As written for the answer booklet: the diagram carries the working, the lines stay short. Read here only; it is not offered as a download.

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Read the whole 2020 solution2020 question paper

CoversBulky substituentsdiene conformationDiels–Alder selectivity

All parts of Question 10