Industrial synthesis of optically active compounds

The history of optical isomerism goes back to the year 1815, when the phenomenon was discovered by the French physicist Jean-Baptist Biot [1]. Optical activity was defined as the ability of a substance to rotate the plane of polarisation of light. Some years later, his student, Louis Pasteur [2] proposed that this optical activity of certain organic compounds was a consequence of their molecular asymmetry, that produces non-super-imposable mirror-image structures. A molecule which is not super-imposable on its mirror image is said to be chiral Conversely, a molecule which is superimposable on its mirror image is described as achiral 

A full discussion of the principles of stereochemistry, together with definitions and nomenclature is beyond the scope of this account. For this purpose the reader is referred to the many excellent works available [3-6]. 

The present discussion is by necessity, selective, and concentrates mainly on examples which, as much as possible, demonstrate environmental principles. The reader is referred to the excellent work of Sheldon [7] for a more comprehensive account of industrial synthesis of optically active compounds. 

Although enantiomers have identical chemical properties in an achiral environment, this is not the case for biological properties. This is because nature itself is dissymmetrical. The enantiomer most potent for a particular or desired action is known as the eutomer, and the other one - often 

Of the two thousand or so drug substances currently marketed worldwide, over 70% are synthetic. The remainder are derived either directly, or by semi-synthesis, from natural sources. Those in the latter category, perhaps not surprisingly, are overwhelmingly single enantiomer compounds. Examples include naturally occurring substances such as quini-dine/quinine and the semi-synthetic beta lactam antibiotic ampicillin. 

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R. A. Sheldon, Chirotechnology Industrial Synthesis of Optically Active Compounds, Marcel Dekker, Inc., New York, 1993. 

Sheldon RA (1993) Chirotechnology industrial synthesis of optically active compounds. Marcel Dekker, New York Basel Hong Kong... 

M. K. O Brien and B. Vanase, Curr. Opin. Drug Discovery Dev., 3,793-806 (2000) R. A Sheldon, Ed., Chirotechnology Industrial Synthesis of Optically Active Compounds, Marcel Dekker, New York, 1993. 

R. A, Sheldon, The industrial synthesis of optically active compounds. Proceedings of Chiral Synthesis Symposium and Workshop, Manchester, England, Spring Innovations, Stockport, 1989, pp. 21-29. 

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