Question

Identify the reagents used for the following conversion

• A. A = LiAlH₄, B = NaOH_(aq), C = NH₂–NH₂/KOH, ethylene glycol
• B. A = LiAlH₄, B = NaOH_(alc), C =Zn/HCl
• C. A = DIBAL-H, B= NaOH_(aq), C = NH₂–NH₂/KOH, ethylene glycol
• D. A = DIBAL-H, B = NaOH_(alc), C = Zn/HCl

Answer 1

The Correct Option is D

In this reaction, the following steps occur:

Step A: Reduction of ester to aldehyde using DIBAL-H (Diisobutylaluminum hydride), a selective reducing agent that reduces esters to aldehydes without affecting other functional groups.

Step B: Aldol condensation, which involves the formation of an intramolecular aldol product. This reaction is catalyzed by NaOH (alc) (sodium hydroxide in alcoholic solution).

Step C: Reduction of the product to alcohol using Zn/HCl in the Clemmensen reduction method, which reduces aldehydes to alcohols.

Thus, the correct reagents are 4, which corresponds to:  
- \( A = \text{DIBAL-H} \)  
- \( B = \text{NaOH (alc)} \)  
- \( C = \text{Zn/HCl} \).

The Correct Answer is: A = DIBAL-H, B = NaOH_(alc), C = Zn/HCl