Introduction and overview - why study organic reaction mechanisms

1 Introduction and overview - why study organic reaction mechanisms  

The first sentence of Hammett s influential book, Physical Organic Chemistry, states, A major part of the job of the chemist is the prediction and control of the course of chemical reactions [3a]. Hammett then explains that one approach is the application of broadly ranging principles, but another involves bit-by-bit development of empirical generalizations, aided by theories of approximate validity whenever they seem either to rationalize a useful empirical conclusion or to suggest interesting lines of experimental investigation . 

Mechanistic considerations based on product studies form the early stages of the bit-by-bit development. The structure of the product, along with that of the starting material, defines the chemical reaction and is the starting point for mechanistic investigations. After the structures of the products of a reaction have been determined, paper mechanisms can be drawn these are mechanistic hypotheses, based as much as possible on precedents and analogies, on which further experimental investigations can be based. Unexpected results are of particular interest. 

Spectroscopic techniques may provide stereochemical information, from which useful mechanistic deductions can be made (Section 2.3.1). Some of the most surprising (but also 

Reaction monitoring is usually beneficial. Even for well-established syntheses, the progress of organic reactions is often monitored qualitatively by chromatographic techniques, most simply by TLC, to determine the reaction time , i.e. when the starting materials have been consumed. Application of standard quantitative chromatographic methods, e.g. GC or 

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