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Question #44373

Difficulty: 8/10 | 🟢 Free

The Question

Consider the organic substrate 6-hepten-2-one. It is subjected to two independent reaction sequences to yield major products $\textbf{X}$ and $\textbf{Y}$ .

Sequence I: $\ce{6-hepten-2-one ->[1. LiAlH_4 (excess), Et_2O][2. H_3O^+] \textbf{X}}$

Sequence II: $\ce{6-hepten-2-one ->[1. BH_3 \cdot THF (excess)][2. H_2O_2, NaOH, H_2O] \textbf{Y}}$

Which of the following correctly identifies the structures of the major products $\textbf{X}$ and $\textbf{Y}$ ?

Options

A.
$\textbf{X}$ is 6-hepten-2-ol; $\textbf{Y}$ is heptane-1,6-diol
B.
$\textbf{X}$ is 6-hepten-2-ol; $\textbf{Y}$ is 7-hydroxyheptan-2-one
C.
$\textbf{X}$ is heptan-2-ol; $\textbf{Y}$ is heptane-1,6-diol
D.
$\textbf{X}$ is heptane-1,6-diol; $\textbf{Y}$ is 7-hydroxyheptan-2-one

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

Hydroboration-Oxidation Regiochemistry|Reduction Selectivity (Hydrides)|Reduction Selectivity (Sn/HCl vs LiAlH4)

Why This Question Is Tricky

Common Mistakes

This problem tests the chemoselectivity of reducing agents, specifically targeting the widespread misconception that $\ce{BH_3 \cdot THF}$ is exclusively an alkene-selective hydroboration reagent.

While students correctly recall that $\ce{LiAlH_4}$ reduces ketones but leaves isolated alkenes untouched, they frequently overlook that Borane ( $\ce{BH_3}$ ) is a potent electrophilic reducing agent that also reduces ketones and aldehydes to alcohols.

The trap (Option B) catches students who assume the ketone remains unreacted during the hydroboration-oxidation sequence, which would incorrectly yield 7-hydroxyheptan-2-one.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Alcohols, Phenols, and Ethers - Class 12
Concept	Hydroboration-Oxidation Regiochemistry
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free