CM1000 – Organic Chemistry An Introduction to Functional Group Chemistry Dr. Stuart Collins Recommended text: Hart, Craine, Hart, Organic Chemistry 11 th Edition

Course Content Chapter 6- Organic Halogen Compounds Chapter 7- Alcohols, Phenols and Thiols Chapter 9- Aldehydes and Ketones Chapter 10- Carboxylic Acids and Their Derivatives Chapter 11- Amines and Related Nitrogen Compounds

Organic Chemistry StructureReactivity Carbon Framework Functional Groups Characteristic Behaviour - Can be rationalised and predicted Significance? Design of structureFunction Synthesis

Organic Halogen Compounds Why important? –CFC’s Chlorofluorocarbons (p.196) Environmental Impact –Insecticides (p.198) –Key Synthetic Intermediates Provide Access To A Wide Range Of Organic Compounds General Structure

Classification- Depends on Degree of Substitution

Reactivity Strongly Influenced by Degree of Substitution Nucleophilic Substitution Halide displaced by an incoming nucleophile- a species with an electron pair. Nucleophile can be neutral or anionic

Recall X more electronegative than C – Bond is polarised One covalent bond broken (C-X) One new covalent bond (C-Nu)

Neutral Nucleophiles

Williamson Ether Synthesis

Elimination Reactions- Dehydrohalogenation (6.7) Loss of halide (X - ) from one carbon and loss of a proton (H + ) from adjacent carbon- new alkene Usually occurs on treatment with a base e.g. Na + - OEt

Bases Commonly used to Promote Elimination Reactions

Mechanism

Elimination can occur from either side of the alkyl bromide - 2 alkenes (Regioisomers) Example

Both cis and trans isomers can be formed in the internal elimination Cis and trans isomers can be formed in some cases

Elimination/Substitution- May be competing reactions

By altering the reaction conditions can favour either elimination or substitution -Vary solvent (Polar/Non-Polar) -Vary base or nucleophile In general strong bases favour elimination Nucleophiles which are weak bases favour substitution