Organic Chemistry Basics

Functional Groups

• A functional group is a specific group of atoms within a molecule that determines its chemical properties and reactivity
• Common functional groups:
  • Hydroxyl (-OH)
  • Carboxyl (-COOH)
  • Amino (-NH2)
  • Aldehyde (-CHO)
  • Ketone (-CO-)
  • Ester (-COO-)
  • Ether (-O-)
• Functional groups can be classified as:
  • Hydrophilic (water-loving) or hydrophobic (water-fearing)
  • Acidic or basic
  • Electron-withdrawing or electron-donating

Alkanes

• Alkanes are saturated hydrocarbons with the general formula CnH2n+2
• They are non-polar and non-reactive
• Physical properties:
  • Boiling points increase with increasing molecular weight
  • Melting points increase with increasing molecular weight
  • Density increases with increasing molecular weight
• Chemical properties:
  • Alkanes are resistant to oxidation and reduction
  • They undergo combustion reactions with oxygen
  • They can undergo substitution reactions with halogens

Alkenes

• Alkenes are unsaturated hydrocarbons with one or more carbon-carbon double bonds
• They are more reactive than alkanes due to the presence of the double bond
• Physical properties:
  • Boiling points are generally lower than those of alkanes
  • Melting points are generally lower than those of alkanes
  • Density is generally lower than that of alkanes
• Chemical properties:
  • Alkenes undergo addition reactions with electrophiles
  • They can undergo polymerization reactions
  • They can undergo oxidation reactions

Stereochemistry

• Stereochemistry is the study of the three-dimensional arrangement of atoms in molecules
• Stereoisomers:
  • Enantiomers: non-superimposable mirror images
  • Diastereomers: non-superimposable non-mirror images
• Chirality:
  • A chiral molecule is one that cannot be superimposed on its mirror image
  • Chiral molecules can rotate plane-polarized light
• Stereocenters:
  • A stereocenter is an atom that has a non-superimposable arrangement of atoms bonded to it
  • Stereocenters can be asymmetric or symmetric

Synthetic Reactions

• Synthetic reactions are reactions used to form new molecules
• Types of synthetic reactions:
  • Substitution reactions: replacement of a functional group with another
  • Elimination reactions: removal of a functional group to form a new bond
  • Addition reactions: formation of a new bond by adding a functional group
  • Rearrangement reactions: reorganization of a molecule's structure
• Synthetic reactions can be classified as:
  • Electrophilic reactions: involve the attack of an electrophile (electron-deficient species)
  • Nucleophilic reactions: involve the attack of a nucleophile (electron-rich species)

Nomenclature

• Nomenclature is the system of naming organic compounds
• IUPAC (International Union of Pure and Applied Chemistry) rules:
  • Identify the parent chain (longest continuous chain)
  • Identify the functional groups and their locations
  • Assign a prefix and suffix to the parent chain
  • Use Greek letters to indicate the location of substituents
• Common prefixes:
  • Meth- (one carbon)
  • Eth- (two carbons)
  • Prop- (three carbons)
  • But- (four carbons)
• Common suffixes:
  • -ane (alkane)
  • -ene (alkene)
  • -ol (alcohol)
  • -al (aldehyde)
  • -one (ketone)