Ch. 5 - ChiralitySee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

According to IUPAC protocol, each molecule must have a unique, unambiguous name – even stereoisomers.

Concept #1: Why stereoisomers need their own naming system.  

Rules for the R and S Naming System

Step 1: Assign priorities to the four atoms on the chiral center according to their atomic mass on the periodic table. 

Concept #2: R and S Naming- Step 1  

Step 2: When there is a tie between atomic weights, compare the next set of adjacent atoms (playoffs!)

Concept #3: R and S Naming- Step 2  

Step 3: Double bonds count twice. Triple bonds count three times

Concept #4: R and S Naming- Step 3  

Example #1: Determine priorities for the following chiral center.

Example #2: Determine priorities for the following chiral center.

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

Concept #5: R and S Naming- Step 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.

  • R becomes S
  • S becomes R

Concept #6: R and S Naming- Step 5  

Provide the full name of the following molecule including R & S. 

Practice: Provide the full name for the following molecule, taking stereochemistry into account.

Provide the full name of the following molecule including R & S. 

Practice: Provide the full name for the following molecule, taking stereochemistry into account.

Provide the full name of the following molecule including R & S. 

Practice: Provide the full name for the following molecule, taking stereochemistry into account.