According to IUPAC protocol, each molecule must have a unique, unambiguous name – even stereoisomers.
Step 1: Assign priorities to the four atoms on the chiral center according to their atomic mass on the periodic table.
Step 2: When there is a tie between atomic weights, compare the next set of adjacent atoms (playoffs!)
Step 3: Double bonds count twice. Triple bonds count three times
Example: Determine priorities for the following chiral center.3m
Step 4: If the last priority group is in the back, then trace a path from highest to lowest priority
- Clockwise = R, Counterclockwise = S
- Always Ignore group 4
Step 5: If the last priority group is NOT in the back, swap that group with the group that is on the dash.
- Trace path as always, but this time swap the sign since you swapped groups.
Example: Provide the full name for the following molecule, taking stereochemistry into account.7m
Example: Provide the full name for the following molecule, taking stereochemistry into account.8m