Stereoisomers in Molecules with Two Chiral Centers
The number of possible stereoisomers of a molecule is related to the number of chiral centers present in a molecule.
The exact relationship is m = 2n
Thus, for molecules with two chiral centers there are four possible stereoismers. (More complicated systems will not be considered here.)
where m is the number of possible isomers and n is the number of chiral centers.
Consider the stereoisomers of 2-bromo-3-fluorobutane: