Question

The total number of stereoisomers that can exist for below compounds is:

• A. 4
• B. 2
• C. 3
• D. 6

Answer 1

The correct option is B 2

Although the compound has two chiral carbons, it does not has four optically active isomers as expected. It is due to its existence in cis-form only.
The compound does not show geometrical isomerism due to resticted rotation about the bridge head carbons, hence it remains in cis-form and only mirror image exists.