A spirane consists of two rings sharing a single central spiro carbon. If an appropriately substitut — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

In stereochemistry, a rigid cycloalkane ring acts mathematically identical to a $\pi$ -bond. A 3-ring spirane is topologically equivalent to an odd-numbered cumulene (3 double bonds). In odd cumulenes, the terminal substituent groups are forced back into a perfectly co-planar orientation. Because they are coplanar, appropriately substituted ends will successfully exhibit Geometrical Isomerism, but will possess a Plane of Symmetry, making them optically inactive.