Organic Chemistry: Stereochemistry

Stereochemistry

Definition

• Stereochemistry is the study of the three-dimensional arrangement of atoms in molecules
• It deals with the spatial relationships between atoms in a molecule and the resulting properties

Stereoisomers

• Stereoisomers are molecules with the same bond order and atom connectivity, but differing in their 3D arrangement
• There are two main types of stereoisomers:
  1. Enantiomers: non-superimposable mirror images
  2. Diastereomers: non-mirror image stereoisomers

Chirality

• Chirality refers to the property of a molecule being non-superimposable on its mirror image
• A chiral molecule has a non-superimposable mirror image
• Chiral molecules can rotate plane-polarized light in opposite directions (optical activity)

Stereochemical Notation

• R/S notation: a system for describing the stereochemistry of a molecule using R (rectus) and S (sinister) prefixes
• Cahn-Ingold-Prelog (CIP) rules: a set of rules for assigning R/S notation to a molecule
• Fischer projections: a way of drawing molecules to show their stereochemistry

Stereochemical Properties

• Optical activity: the ability of a chiral molecule to rotate plane-polarized light
• Stereochemical stability: the relative stability of different stereoisomers
• Stereochemical reactivity: the influence of stereochemistry on chemical reactions

Importance of Stereochemistry

• Stereochemistry plays a crucial role in many areas, including:
  • Pharmaceutical development: many drugs have stereoisomers with different biological activities
  • Biological systems: enzymes and other biomolecules often exhibit stereoselectivity
  • Materials science: stereochemistry can influence the properties of materials

Stereochemistry

Definition

• Study of the three-dimensional arrangement of atoms in molecules
• Examines spatial relationships between atoms and resulting properties

Stereoisomers

• Molecules with same bond order and atom connectivity but differing in 3D arrangement
• Two main types: Enantiomers and Diastereomers
• Enantiomers: non-superimposable mirror images
• Diastereomers: non-mirror image stereoisomers

Chirality

• Property of a molecule being non-superimposable on its mirror image
• Chiral molecule has a non-superimposable mirror image
• Can rotate plane-polarized light in opposite directions (optical activity)

Stereochemical Notation

• R/S notation: system for describing stereochemistry using R and S prefixes
• Cahn-Ingold-Prelog (CIP) rules: set of rules for assigning R/S notation
• Fischer projections: way of drawing molecules to show stereochemistry

Stereochemical Properties

• Optical activity: ability of a chiral molecule to rotate plane-polarized light
• Stereochemical stability: relative stability of different stereoisomers
• Stereochemical reactivity: influence of stereochemistry on chemical reactions

Importance of Stereochemistry

• Crucial role in pharmaceutical development: stereoisomers with different biological activities
• Importance in biological systems: enzymes and biomolecules exhibit stereoselectivity
• Influence on materials science: stereochemistry affects material properties

Test your knowledge on the three-dimensional arrangement of atoms in molecules, including stereoisomers and their properties.