Before You Begin

Question #44464

Difficulty: 8/10 | 🟢 Free

The Question

Consider the electrophilic addition of $\ce{HCl}$ (1 equivalent) to optically pure (1R, 4S)-1-methylbicyclo[2.2.1]hept-2-ene in an inert solvent ( $\ce{CCl4}$ ) at 298 K. The reaction proceeds via a carbocation intermediate to yield a major optically active product $\mathbf{P}$ . Assuming thermodynamic and kinetic control align due to the stability of the intermediate, identify the correct IUPAC name and stereochemistry of product $\mathbf{P}$ .

Options

A.
(1S, 2R, 4R)-2-chloro-2-methylbicyclo[2.2.1]heptane
B.
(1R, 2S, 4S)-2-chloro-1-methylbicyclo[2.2.1]heptane
C.
(1S, 2S, 4R)-2-chloro-2-methylbicyclo[2.2.1]heptane
D.
(1R, 2R, 4S)-2-chloro-1-methylbicyclo[2.2.1]heptane

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

Alkene Addition Regioselectivity|Optical Activity and Enantiomers|Cycloalkane Ring Strain|Cahn-Ingold-Prelog (CIP) Priority

Why This Question Is Tricky

Common Mistakes

This question tests the student's ability to recognize when standard Markovnikov addition is overridden by skeletal rearrangement and steric constraints.

The core trap is blindly applying Markovnikov's rule to predict direct chloride attack at C2 without rearrangement (Option B).

The hidden variable is the Wagner-Meerwein shift driven by the formation of a more stable tertiary non-classical carbocation, which changes the connectivity.

Furthermore, the student must understand that the rigid bicyclic framework dictates an exclusive exo-attack, overriding simple thermodynamic stability of the substituents, and correctly map the 3D rearrangement to assign the final Cahn-Ingold-Prelog (CIP) configuration.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Hydrocarbons - Class 11 Part 2
Concept	Alkene Addition Regioselectivity
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free