Overview
The lecture covers the most important organic chemistry functional groups, their structures, names, and characteristic features for study and recognition.
Hydrocarbons and Basic Groups
- Alkanes are hydrocarbons with only single carbon-hydrogen bonds (e.g., pentane: 5 carbons).
- Alkenes contain at least one carbon-carbon double bond (e.g., 2-butene).
- Alkynes have at least one carbon-carbon triple bond (e.g., 2-butyne).
- Cycloalkanes are ring-shaped alkanes with only single bonds (e.g., cyclopentane).
- Aromatic rings feature alternating double bonds in a ring (benzene is a key example).
Halogen and Oxygen-containing Groups
- Alkyl halides (haloalkanes): hydrocarbons containing halogen atoms (R–X, where X = Cl, Br, F, I).
- Ethers have an oxygen bond between two carbon groups (R–O–R').
- Alcohols contain a hydroxyl group (R–OH); named by position on the chain (e.g., 1-butanol).
Carbonyl-containing Groups
- Ketones have a carbonyl group (C=O) within the carbon chain (e.g., 2-pentanone).
- Aldehydes have a carbonyl group at the end of the chain (suffix "-al", e.g., hexanal).
- Carboxylic acids contain a carboxyl group (R–COOH, e.g., hexanoic acid).
- Esters have the structure R–COO–R'; named as alkyl alkanoates (e.g., methyl ethanoate).
- Acid anhydrides are compounds with two acyl groups bonded to the same oxygen.
- Acid chlorides (or other halides) have acyl groups bonded to a halogen (e.g., acetyl chloride).
Nitrogen and Sulfur-containing Groups
- Amines contain an amino group (R–NH₂, e.g., methylamine).
- Amides have a carbonyl attached to an amino group (R–CONH₂, e.g., butanamide).
- Nitriles contain a carbon–nitrogen triple bond (R–C≡N, e.g., ethanenitrile).
- Thiols have an –SH group; similar to alcohols, but with sulfur instead of oxygen.
- Thioethers (R–S–R') and thioesters (R–COS–R') have sulfur replacing oxygen in ethers and esters.
- Enols combine an alkene (C=C) and alcohol (OH) group.
- Enamines have a double bond next to a nitrogen atom.
- Imines have a carbon–nitrogen double bond (C=N).
- Nitro groups consist of –NO₂.
Other Functional Groups
- Organic peroxides have two oxygen atoms bonded together (–O–O–).
- Peroxy acids have both a carboxylic acid and peroxide group.
- Carbocations (positively charged carbon), carbanions (negatively charged carbon), radicals (odd electron), and carbenes (neutral carbon with two bonds) are important reactive species.
Key Terms & Definitions
- Alkane — Hydrocarbon with only single C–C bonds.
- Alkene — Hydrocarbon with at least one C=C double bond.
- Alkyne — Hydrocarbon with at least one C≡C triple bond.
- Cycloalkane — Ring-shaped alkane.
- Aromatic ring (benzene) — Cyclic with alternating double bonds.
- Alkyl halide / haloalkane — Hydrocarbon with a bonded halogen.
- Ether — Oxygen atom bonded to two carbon chains.
- Alcohol — Contains an –OH (hydroxyl) group.
- Ketone — Carbonyl group bonded to two carbons.
- Aldehyde — Carbonyl group at carbon chain end.
- Carboxylic acid — Contains –COOH group.
- Ester — Contains –COO– between carbon groups.
- Acid anhydride — Two acyl groups bonded to one oxygen.
- Acid chloride — Acyl group bonded to halogen.
- Amine — Contains an amino group (–NH₂).
- Amide — Carbonyl attached to amino group.
- Nitrile — Carbon–nitrogen triple bond.
- Thiol — Contains an –SH group.
- Thioether/Thioester — Sulfur analogs of ether/ester.
- Enol — Alkene with an alcohol group.
- Enamine — Alkene with an amine group.
- Imine — C=N double bond.
- Nitro group — –NO₂.
- Peroxide — –O–O– bond.
- Peroxy acid — Carboxylic acid with a peroxide.
- Carbocation, Carbanion, Radical, Carbene — Different reactive carbon species.
Action Items / Next Steps
- Memorize the structures and names of all common functional groups.
- Practice identifying these groups in various molecules.
- Review any assigned textbook readings on functional groups.