Chemical Reaction Mechanisms
Objectives
By the end of this course unit, the student should be able to understand and interpret chemical processes through a mechanistic approach, recognizing that these processes are not fixed and unchanging but rather dynamic concepts that require continuous study. Mechanisms are descriptions based on the best available evidence and are modified and updated as new data emerge. The mechanistic approach should avoid the tendency to memorize chemical reactions; instead, it should focus on understanding the factors responsible for the observed outcomes. The primary advantage of a mechanistic approach lies in its ability to use a small set of guiding principles to explain and correlate experimental results and predict the outcomes of changes in the conditions of known reactions, even in the face of diverse information.
General characterization
Code
10710
Credits
6.0
Responsible teacher
Luísa Maria da Silva Pinto Ferreira
Hours
Weekly - 4
Total - 56
Teaching language
Português
Prerequisites
na
Bibliography
Felix A. Carroll, Perspectives on Structure and Mechanism in Organic Chemistry, Wiley, 2010.
P. A. Sykes, A Primer to Mechanism in Organic Chemistry, Longman Scientific & Technical: Essex, 1995.
H. Maskill, Mechanisms of Organic Reactions, Oxford Chemistry Primers, 45, ed. S. G. Davies: Oxford Science Pub., Oxford Univ. Press, 1996.
P. A. Sykes, A Guidebook to Mechanism in Organic Chemistry, 6 ed., Longman, 1985.
Teaching method
Available soon
Evaluation method
Available soon
Subject matter
Review of some basic principles: Structure and reactivity. Thermodynamic and kinetic effects associated with reactional mechanisms. Elementary reactions, concerted mechanism, activated complex, transition state, molecularity, reaction coordinates, kinetic and thermodynamic control, Hammond''''s postulate. Stability of ionic intermediates, output groups, nucleophiles, electrophiles, bases, and acids. Acid/base characteristics. Methods of investigating mechanisms: kinetic and non-kinetic. Ionic intermediates. Study and elaboration of reaction mechanisms. Mechanisms, stereoelectronic effects and isotopic effects. HOMO and LUMO boundary orbitals and preferential interactions in ionic reactions. Soft and hard center concept. Preferential interactions of boundary orbitals in the interpretation of bidentate nucleophile reactivity. Reactions involving nucleophiles and bases. Reactions involving electrophiles. Reactions involving neutral reactive species (carbenes and nitrenes, arynes, and free radicals). Rearrangements (pinacol, Favorskii, Baeyer-Villiger, Beckmann) and intermediates containing electrodeficient nitrogen and oxygen atoms. Anomeric effect. Intermediate-free reactions (pericyclic reactions). Reaction mechanisms of aromatic systems. Mechanisms in radical processes. Cyclization reactions (Baldwin''''s rules). Examples of molecules in biological systems and some mechanistic issues: Amino acids, peptides and proteins. Some examples of amino acid synthesis. Example of polypeptide and protein analysis. Sanger''''s method for determining N-terminal residue.
Prediction of synthetic processes of simple molecules based on mechanistic analysis.