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Question #44446

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following reaction sequence: $\ce{3-methylbutan-2-one ->[HCN, \ KCN \ (cat.)] \textbf{P}}$ $\ce{\textbf{P} ->[1. \ SnCl_2, \ HCl \ (dry \ ether)][2. \ H_3O^+, \ \Delta] \textbf{Q} \ (major \ product)}$ What is the correct IUPAC name of compound $\textbf{Q}$ ?

Options

A.
2-hydroxy-2,3-dimethylbutanal
B.
2-hydroxy-2,3-dimethylbutanoic acid
C.
1-amino-2,3-dimethylbutan-2-ol
D.
2-hydroxy-2-isopropylpropanal

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Cyanohydrin Stereochemistry|Reduction Selectivity (Sn/HCl vs LiAlH4)|Nucleophilic Acyl Substitution

Why This Question Is Tricky

Common Mistakes

The question tests the chemoselectivity of Stephen reduction (\ce{SnCl2/HCl}) on a cyanohydrin, specifically targeting the nitrile group to form an aldehyde.

This avoids the common student traps of assuming full hydrolysis to a carboxylic acid (Option B) or full reduction to an amine (Option C).

Additionally, it tests the stability of the alpha-hydroxy group under acidic conditions (resisting dehydration due to the adjacent electron-withdrawing group) and rigorous application of IUPAC nomenclature rules for selecting the principal carbon chain over a branched substituent (Option D).

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Aldehydes, Ketones, and Carboxylic Acids - Class 12
Concept	Cyanohydrin Stereochemistry
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free