# What are the chiral centers of the molecule of nicotine?

Nov 24, 2015

There's only one, and it's S.

The highest to lowest priority is (1,2,3,4):

• tertiary amine (highest atomic number here; $- {\text{NC}}_{2}$)
• aromatic $s {p}^{2}$ (taken similar to tert-butyl, i.e. $- {\text{CC}}_{3}$)
• methylene ($- {\text{CH}}_{2}$)
• hydride ($- \text{H}$)

You get that from going clockwise and crossing the hydride, but since the hydride is facing forwards rather than backwards, the configuration is the reverse of R, which is S.