Terminology of stereochemistry

JP Moss. Basic terminology of stereochemistry. Pure Appl. Chem. 68, 2193, 1996. 

Basic Terminology of Stereochemistry hitp //www,chem.qmut.ac.uk/iupac/siereo/ Enzyme Nomenclature http //www.chein.qimil.ac.uk/iubmb/enzyme/... 

Within the commonly accepted terminology of stereochemistry, molecular shape is understood as being the three-dimensional arrangement of formal chemical bonds. Most approaches toward the visualization of stereochemical arrangements of atoms... 

Most organic molecules in living organisms contain asymmetrical centers (i.e., they are chiral). (The terminology of stereochemistry has been reviewed by Moss.1) For example, amino acids that are incorporated into proteins are L and sugars in carbohydrates are D. It is understandable that the three-dimensional structures of the receptors in proteins for small molecules will favor only one optical isomer (i.e., the one that fits sterically, hydrogen bonds properly, and so on). Most compounds made for use by plants and animals will have to be single optical isomers. 

This definition is taken from Basic Terminology of Stereochemistry lUPAC Recommendations 1996 (1996) Pure and Applied Chemistry, vol. 68, p. 2193. 

International Union of Pure and Applied Chemistry, Basic Terminology of Stereochemistry, Moss, G. R, Ed., Pure Applied Chemistry, 68, 2193,1996. 

Fig. 10.3 Prostereogenic centers due to stereoheterotopic relationships of different types in the conventional terminology of stereochemistry, where the ligands a, b, and X represents achiral ligands in isolation and the ligand p represents a chiral ligand that is the mirror image of a chiral...

Figure 10.3 summarizes topicity relationships in the conventional terminology of stereochemistry. The two achiral ligands X s in 4 (the ligands a and b are also achiral in isolation) are enantiotopic to each other, while the two achiral ligands X s in 5 (a achiral, p chiral in isolation) as well as the two achiral ligands X s in 6 (p and p enantiomeric in isolation) are diastereotopic to each other. The difference between the enantiotopic X s in 4 and the diastereotopic X s in 5 (or 6) stems from difference in their substitution products (enantiomers vs. diastereomers ). 

The problems of various types in the conventional stereochemistry are highly entangled as the result of the semantic transmutation described in the preceding subsections. It is impossible to solve the entangled problems if we maintain the conventional terminology of stereochemistry. Hence, the conventional terminology should be entirely reconsidered to restructure stereochemistry. 

Moss GP (1996) Basic terminology of stereochemistry (lUPAC recommendations 1996). Pure Appl Chem 68 2193-2222, p. 2203, Blue Book, p. 479... 

There was considerable ambiguity and imprecision in the terminology of stereochemistry as it developed during the 20th century. In recent years, stereochemical terminology has clarified. We present here a discussion of the basics, not focused solely on carbon. However, in Section 6.2.4 we will examine carbon specifically. While most of this should be review, perhaps the perspective and some of the terminology will be new. 

Basic Terminology of Stereochemistry, http //www.chem.qmul.ac.uk/ iupac/stereo/. A web version of the original document published by lUPAC [64]. The original document is available for download at the web page as well. 

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