Description:
| Aims: To provide the student with a working knowledge of important classes of organic transformations and illustrate how the rate and mechanism of a chemical reaction can be understood in terms of the chemical structure of molecules. To show how experimental kinetic data may be used to elucidate chemical reaction mechanisms.
Learning Outcomes: After studying this Unit, students should be able to:
* Describe the synthetic chemistry of carbocations, anions and radical species and describe some of the mechanisms involved in their reaction.
* analyse experimental rate data for first- and second-order reactions;
* describe how the involvement of a reaction intermediate may be deduced;
* discuss the stereochemistry of aliphatic nucleophilic substitution;
* describe the effects of added ions upon SN1 substitutions;
* discuss the role of ion pairs in unimolecular solvolyses;
* determine the pH of a buffer solution;
* describe the effect of pH on the rates of acid or base catalysed reactions;
* distinguish general catalysis from specific catalysis by acids or bases;
* describe the features of nucleophilic catalysis;
* rationalise the reactivity of molecules using stereoelectronic principles.
Skills: Problem solving (T, F, A), Data Analysis (T, F, A), Independent working (F), Group working (F).
Content: Aliphatic nucleophilic substitution: 1st & 2nd order kinetics, competing reactions; Deduction of reaction mechanism, evidence for intermediates; Stereochemical evidence for the SN2 mechanism; Evidence for the SN1 mechanism: consecutive reactions, common-ion effect, solvolysis, ion pairs; Acid/base catalysis: solvent levelling, buffers, specific & general catalysis; Nucleophilic catalysis.
Review of basic stereochemistry principles. The importance of stereoselective synthesis. Diastereomers and diastereoselective synthesis. Conformation of cyclohexanes - the importance of stereochemistry to reactivity - carbohydrates. Stereochemistry and mechanism. Frontier Molecular Orbital Theory and stereoelectronic effects. Aspects of the chemistry of carbocations, carbanions, radicals, carbenes, nitrenes, and arynes.
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