Organic Reaction Mechanisms
Faculdade de Ciências e Tecnologia
Departamento de Química
Teacher in charge
Maria Teresa Barros Silva
It is of interest to use a mechanistic approach which permits the use of a small number of principles derived from a large amount of data to explain and predict experimental results and the consequences of altering conditions for known reactions. Small molecules are typically used for this purpose but the use of biologically important molecules could alert us to some specific characteristics of living systems.
Extensive knowledge in Organic chemistry, Introduction to physical chemistry and thermodynamics. Stereochemistry.
Revision of Some basic principles Structure and Reactivity. Thermodynamic and kinetic effects associated with reaction mechanisms. Elementary reactions, concerted mechanisms, activated complex, transition state, molecularity, Reaction coordinates, kinetic and thermodynamic control, Hammond postulate. Stability of ionic intermediates, leaving groups, nucleophiles, electrophiles, acids and bases. Acid/base characteristics. Methods for investigating reaction mechanisms; kinetic and non-kinetic. Ionic intermediates. Study and Determination of Reaction Mechanisms Mechanism and molecular orbitals. Stereoelectronic effects. Reactions involving nucleophiles and bases. Reactions involving electrophiles and acids. Reactions involving neutral reactive species (carbenes, nitrenes, Arynes and free radicals. Rearrangments (pinacol, Curtius, Favorski, Baeyer-Villiger, Beckmann) and intermediates containing electron deficient nitrogen and oxygen atoms. Annomeric effect. Reactions without intermediates (concerted pericyclic reactions). Mechanisms in aromatic systems. Mechanisms in radical reactions. Cyclisation reactions (Baldwin rules). Ex. of mechanisms in biological systems.
P. A. Sykes, A Guidebook to Mechanism in Organic Chemistry,7 ed., Longman, 1980. M. Hornby, J. Peach, : Foundations of Organic Chemistry, Oxford Chemistry Primers, 9, ed. S. G. Davies Oxford Science Publications, Oxford University Press, (1993). H. Maskill, Mechanisms of Organic Reactions, Oxford Chemistry Primers, 45, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1996). C. J. Moody, G.H. Whitham, Reactive Intermediates, Oxford Chemistry Primers, 8, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1992). J. Jones, Core Carbonyl Chemistry, Oxford Chemistry Primers, 47, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1997). G. D. Meakins, Functional Groups: Characteristics and Interconversions, Oxford Chemistry Primers, 35, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1996). A. J. Kirby, Stereoelectronic Effects, Oxford Chemistry Primers, 36, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1996). M. Sainsbury, Aromatic Chemistry, Oxford Chemistry Primers, 4, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1992). L. M. Harwood, Polar Rearrangements, Oxford Chemistry Primers, 5, ed. S. G. Davies: Oxford Science Publications, Oxford University Press, (1992). H.Lowry and K.S. Richardson , Mechanism and Theory in Organic Chemistry, 3rd edition, , Harper e Row Publishers, 1987. J.March, Advanced Organic Chemistry, Reactions, Mechanisms and Structure, 3rd edition, Wiley Interscience, 1985.
Theoretical lectures are given in way to avoid monotony. During the lectures experimental results are used to demonstrate concepts which exemplify the importance of the understanding of chemistry. Problems sessions are an essential part of the course and at least four hours per week are dedicated to this. Although in the first sessions the lecturer leads the students into discussions it is expected that later the students will be encouraged take over this initiative.
When justified molecular models are used as a visual aid. 3D graphics and other audio-visual aids are used whenever possible.
Problem sessions are also very important for the lecturer to identify difficulties that the students may have in their understanding and to find solutions to these difficulties by discussion. This is done in such a way that the high level of the course is maintained
Students have access to a web page created on the moodle platform where they will find online weekly tests and support documents for the theoretical and TP classes.
There will be continuous evaluation with tests every week (on line, moodle) and three main tests, one in the middle and one at the end of the semester. Besides the official exams there are alsothree tests during the semester. The first after about 12-14 hours of lectures and the third on completion of the lecture program. These tests permit the student to pass the course although they are encouraged to take the final exam. The first test in particular allows both the students and lecturer to identify any teaching/learning difficulties which can subsequently be corrected early in the course.