Organic Chemistry Basics - Result Question 36

42. The total number of stereoisomers that can exist for $M$ is

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(2015 Adv.)

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Answer:

Correct Answer: 42. (2)

Solution:

  1. Although the compound has two chiral carbons (indicated by stars), it does not has four optically active isomers as expected. It is due to its existence in cis-form only.

cis-form

trans-form (only hypothetical)

The above shown transformation does not exist due to restricted rotation about the bridge head carbons, hence only cis-form and its mirror image exist.