Indian Forest Service (Mains), Chemistry optional · 2021 · Paper II
Q6(a)(ii). Wittig olefination
Question
Predict the major product from benzaldehyde and n-propyltriphenylphosphonium chloride using potassium tert-butoxide, and explain its geometry.
Answer in brief
The expected major alkene is (Z)-1-phenylbut-1-ene, PhCH=CHCH₂CH₃, from an unstabilized ylide.
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CoversWittig reactionunstabilized ylideZ-selectivityoxaphosphetanephosphonium ylide
All parts of Question 6
- 6(a)(i) Malonic ester ring synthesis5 marks
- 6(a)(ii) Wittig olefination5 marks
- 6(b)(i) Tertiary protein structure5 marks
- 6(b)(ii) End-group content of polystyrene5 marks
- 6(c)(i) Cyclization of a beta-hydroxy phenethylamide5 marks
- 6(c)(ii) Terylene from p-xylene5 marks
- 6(d) Fischer indole synthesis5 marks
- 6(e) Acid equivalent of nylon-6,65 marks