Isomers and Stereochemistry - Organic Chemistry Concepts: An EFL Approach - page 54

D This example shows that sometimes you need to look further than the first point
of attachment. You saw this in B where the ethyl and propyl ligands were identified as
different groups.
This is easy to see in acyclic examples, but it is often more difficult to see in cyclic
examples.
Here you only need to look at the C 3 center. The CH 3 and H ligands are simple to see.
The other two substituents, the CH 2 groups at C 2 and C 4 , seem equal at first. As you
move around the ring in either direction, these groups become different at C 1 and C 5 .
Therefore C 3 is a chirality center and the molecule is chiral.
Q 3.9. Mark all of the chirality centers in each of the following molecules.