How can I identify chiral and achiral molecules?

1 Answer
Nov 23, 2015

Look for #sp^3# carbons; those tend to be the most prevalent indications of chirality or achirality. You can ignore many #sp^2# alkene carbons.

Note that only after examining a potential chiral carbon can you determine any achirality it actually has.

After you determine what atoms are stereocenters, if there is an even number of stereocenters, check whether or not the molecule has a symmetry axis dividing down the middle of the stereocenters.

If so, you might have a meso isomer, in which case the molecule as a whole is NOT chiral.

Here is an example of identifying stereocenters in detail:

Can you see that carbons 5, 6, 9, 13, and 14 are stereocenters? Can you identify which configuration they are?

When you figure it out, check out the link above and see what they actually are.