UPSC Combined Geo-Scientist, Mains · 2019 · Mains Paper III
Q6(j). Cyanohydrin acyl-anion equivalent
Question
Benzaldehyde reacts with Me₃SiCN then LDA to A; addition of acetophenone followed by water gives B. Identify both.
Answer in brief
A is the lithiated O-silyl cyanohydrin; after deprotection/cyanide loss, B is PhCOC(OH)(Me)Ph.
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CoversCyanohydrin acyl-anion equivalentUmpolung
All parts of Question 6
- 6(a) Ozonolysis of an exocyclic alkene4 marks
- 6(b) Stability of primary carbocations4 marks
- 6(c) Dehydration of pentan-2-ol4 marks
- 6(d) Peroxide effect4 marks
- 6(e) Fused cyclobutene opening4 marks
- 6(f) Benzyne substitution of p-iodotoluene4 marks
- 6(g) Inductive ether fragmentation4 marks
- 6(h) Schmidt reaction of cinnamic acid4 marks
- 6(i) Heterocycle aromaticity4 marks
- 6(j) Cyanohydrin acyl-anion equivalent4 marks