Further Synthetic Routes Revision notes | A-Level Chemistry OCR

Further Synthetic Routes

This lesson covers:

Summaries of key reactions for aliphatic compounds
Summaries of key reactions for aromatic compounds
How functional groups determine reactivity

Summary of key organic reactions for aliphatic compounds

Below is an overview of the primary types of organic reactions we've discussed for aliphatic compounds.

Flowchart summarising key organic reactions for aliphatic compounds including alkanes, alkenes, alcohols, and carboxylic acids.

Reaction	Reagent and conditions	Reaction type
1	Halogen, UV light	Free radical substitution
2	H₂, Ni catalyst, 150°C	Electrophilic addition
3	Hydrogen halide or halogen	Electrophilic addition
4	NaOH(aq), reflux	Nucleophilic substitution
5	Sodium halide, H₂SO₄, reflux	Nucleophilic substitution
6	Steam, H₃PO₄ catalyst, 300°C, 60 atm	Electrophilic addition
7	Conc. H₂SO₄ catalyst, heat	Elimination
8	Conc. NH₃ in ethanol, heat under pressure	Nucleophilic substitution
9	KCN in ethanol, reflux	Nucleophilic substitution
10	K₂Cr₂O₇(aq), H₂SO₄ catalyst, reflux	Oxidation
11	NaBH₄(aq), heat	Nucleophilic addition
12	K₂Cr₂O₇(aq), H₂SO₄ catalyst, distill	Oxidation
13	NaCN(aq), H₂SO₄ catalyst	Nucleophilic addition
14	Carboxylic acid, conc. H₂SO₄ OR acid anhydride	Condensation
15	H₂O, dilute HCl(aq), heat	Hydrolysis
16	Dilute HCl(aq), reflux	Hydrolysis
17	Alcohol, conc. H₂SO₄	Condensation
18	Dilute NaOH(aq), reflux	Hydrolysis
19	NH₃ or amine	Nucleophilic addition-elimination
20	SOCl₂	Substitution
21	H₂O	Hydrolysis
22	Alcohol	Nucleophilic addition-elimination

Summary of key organic reactions for aromatic compounds

Below is an overview of the primary types of organic reactions we've discussed for aromatic compounds.

Reactions of benzene

Diagram showing key organic reactions for aromatic compounds including nitration, amination, and halogenation.

Reaction	Reagent and conditions	Reaction type
1	Cl₂, AlCl₃ or FeCl₃ catalyst	Electrophilic substitution
2	Conc. HNO₃, conc. HCl, 25-60°C	Electrophilic substitution
3	CH₃Cl, AlCl₃ catalyst, heat	Friedel-Crafts alkylation
4	CH₃COCl, AlCl₃ catalyst, heat	Friedel-Crafts acylation
5	Br₂, AlBr₃ or FeBr₃ catalyst	Electrophilic substitution
6	Sn, conc. HCl, reflux, then NaOH_(aq)	Reduction
7	Br_2(aq)	Electrophilic substitution

Reactions of phenol

Diagram showing key organic reactions for aromatic compounds including ester formation, bromination, nitration, and formation of sodium phenoxide.

Importance of functional groups

Functional groups are responsible for a molecule's chemical properties and reactivity. Organic molecules are categorised by homologous series based on their functional groups.

Some properties and typical reactions associated with key functional groups are:

Homologous series	Functional group	Properties	Typical reactions
Halogenoalkane	C-X	Polar bond	Nucleophilic substitution, Friedel-Crafts alkylation
Aldehyde/Ketone	C=O	Polar C=O bond	Oxidation (aldehydes only), reduction, nucleophilic addition
Nitrile	C≡N	Electron deficient C	Reduction, hydrolysis
Hydroxynitrile	R₂C(OH)C≡N	Electron deficient C	Reduction, hydrolysis
Carboxylic acid	-COOH	Electron deficient C	Neutralisation, condensation, substitution
Ester	RCOOR'	Electron deficient C	Hydrolysis
Amine	C–NR₂	Lone pair on nitrogen is basic and can act as a nucleophile	Neutralisation, nucleophilic substitution
Amide	RCONHR’	Electron deficient C	Hydrolysis
Aromatic compounds	C₆H₅-	Stable delocalised ring of electrons	Electrophilic substitution
Acyl chloride	-COCl	Electron deficient C	Condensation, Friedel-Crafts acylation
Acid anhydride	RCOOCOR'	Electron deficient C	Condensation

So by recognising functional groups, organic chemists can predict the likely behaviour and reactivity of compounds. This allows them to design effective syntheses.