UPSC Combined Geo-Scientist, Mains · 2018 · Mains Paper III
Q7(d). Unsymmetrical benzil synthesis
Question
Convert benzaldehyde into PhCOCOC₆H₄Me with the methyl group para, giving suitable reagents.
Answer in brief
Use a dithiane acyl-anion equivalent, add p-tolualdehyde, then deprotect and oxidise the resulting mixed benzoin.
Part of VKC Basic
Read the key points and the full model answer with VKC Basic
VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.
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.
The handwritten model answer pages open with the VKC plan.
CoversUnsymmetrical benzil synthesisUmpolung synthesis
All parts of Question 7
- 7(a) Epoxidation reactivity5 marks
- 7(b) Substituted aniline basicity5 marks
- 7(c)(i) Dakin oxidation5 marks
- 7(c)(ii) Successive Claisen rearrangements5 marks
- 7(d) Unsymmetrical benzil synthesis5 marks
- 7(e) Bucherer amination5 marks