Examination arrangement

Course content

The course deals with fundamental principles and methods used in physical and mechanistically organic chemistry:

(i) Description of molecules (includes reactive intermediates as radicals, carbenes, carbocations and carbanions) based on the valence bond theory and molecular orbital theory.

(ii) Conformational analysis of organic molecules, NMR analysis of hindered rotation (determination of the rate constant at the coalescence temperature), energy-reaction coordinate diagram for simultaneously rotation of two C-C bonds and a short introduction to molecular mechanic calculations.

(iii) Stereochemistry and symmetry topics. Keywords: prochirality, stereospecific and stereoselective reactions, Cram's rule and Felkin-Ahn's model, symmetry operations, symmetry elements, symmetry point groups and topical relationships related to symmetry.

(iv) Substituent effects: steric, resonance, inductive and field effects.

(v) General tools for mechanistically studies of organic reactions, e.g. crossover experiments (intramolecular or intermolecular reaction?) and isotope labelling experiments (which bonds are broken / formed?).

(vi) Energy surfaces (2D and 3D) and kinetic analyses in the study of reaction mechanisms. Keywords: More O'Ferral-Jencks plot (variable transition-state diagram), reaction order and rate laws, the steady-state approximation in the study of complex reactions, kinetic versus thermodynamic control, the principle of microscopic reversibility, the Curtin-Hammett principle, the Hammond's postulate. Energy functions from rate constants and reaction temperatures: The Arrhenius (activation energy) and the Eyring (enthalpy and entropy of activation) equations. Kinetic isotope effects (primary and secondary).

(vii) Linear free energy relationships (LFERs): (a) The Hammett equation for aromatic compounds, substituent and reaction constants, significance of the Hammett reaction constant values, deviations from linearity - mechanistic information in multi-step reactions. (b) The Swain-Scott equation (nuclophilicity versus basicity). (c) The Grunwald-Winstein and the Schleyer equations (quantifying solvent effects and nucleophilicity).

(viii) Classification of solvents based on physical properties: dielectric constant, refractive index, dipole moment, donor number, acceptor number, hydrogen bond acceptor capacity alpha, hydrogen bond donor capacity beta and the Reichardt's Et scales.

(ix) Acid-base chemistry: gas phase vs. aqueous acidities and acidities in water vs. organic solvents, aqueous pKa scale (leveling effect), chemistry in extremely acidic media, acidity function scale Ho, acid-base catalysis (specific and general), Lewis acid and base (hard / soft).

(x) Detailed mechanistic description and discussion of basic organic reactions using the tools described above for: (a) nucleophilic addition to aldehyde / ketone (acid and base catalysis); (b) hydrolysis of acetal (acid catalysis); (c) hydrolysis of ester (acid and base catalysis); (d) nucleophilic aliphatic substitution (SN2 / SN1, neighboring group assistance, ion pairs, non-classical cations); (e) elimination (E1 / E2 / E1cb, stereo and regiochemistry).

(xi) Pericyclic reactions: electrocyclic, sigmatropic, cycloaddition and cheletropic reactions. Keywords: Woodward and Hoffmann's "selection rules" for thermal and photochemical reactions, MO correlation diagrams.

Learning outcome

After completion of the course the student can demonstrate fundamental understanding in order to:

• describe molecular structure by the use of the valence bonding theory and molecular orbital theory - predict stereoselectivity in reaction involving the attack of nucleophiles on the carbonyl group (Cram's rule and the Felkin Ahn model)
• use kinetics as a tool for understanding reaction mechanisms - use kinetic data for interpretation of reaction mechanisms
• calculate a reactions activation energy, enthalpy of activation and entropy of activation by help of Arrhenius and Eyrings equations
• determine if a reaction is acid or base catalyzed (specific or general catalysis) from kinetic data, and feel comfortable in making estimates on reaction mechanisms by use of the Hammett equation as a tool in studies of organic reactions
• interpret data for the inclusion of isotops and how this can be used in mechanistically studies of organic reactions
• explaining steric and electronic effects in several important reactions Finally the students can demonstrate the ability to choose a suitable solvent for a reaction based on the solvent physical properties and knowledge about the mechanism of the reaction
• connect names to important reactions and reaction mechanisms and be familiar with different types of reaction mechanisms
• propose a reaction mechanism using the principles described above
• suggest additional experiments to "prove" or "disprove" a proposed reaction mechanism - use Woodward and Hoffman's "selection rules" for pericyclic reactions
• deduce MO correlation diagrams for pericyclic reactions
• be comfortable with synthetic approaches involving sustainable methods e.g Green chemistry

Learning methods and activities

Lectures and exercises 4 and 2 hour per week, respectively. Lectures are given in English on request.

Expected work load in the course is 200-225 hours

Further on evaluation

If there is a re-sit examination, the examination form may be changed from written to oral.

Required previous knowledge

Knowledge corresponding to TKJ4102/TKJ4100/KJ1020, TKJ4150 and KJ2022 or similiar courses.

Course materials

E. V. Anslyn; D. A. Dougherty: "Modern Physical Organic Chemistry", University Science Books, 2006. or F. A. Carey; R. J. Sundberg: "Advanced Organic Chemistry, Part A: Structure and Mechanisms, Fifth edition, Springer US, 2007

Credit reductions