Further points on correct terminology

In this section we draw attention to several common errors in terminology relating to asymmetric synthesis. 

The first point, which should be obvious to most readers, is that a tetrahedral centre is properly represented by (22) in which the 

A second area concerns the use of the word chiral. This has a specific definition and can only be properly applied to three-dimensional objects. Thus it is incorrect to refer to a chiral centre/axis or a chiral synthesis . The former can be a chirality centre/axis or a centre/axis of chirality although for most purposes we prefer to replace these terms by stereogenic centre/axis (which is, however, not equivalent). [51 As a collective term for enantio- and diastereoselective 

It is important to realise that chirality is a symmetry property of a whole molecule and cannot be localised in a particular centre or group (although it may be associated with the presence of a particular stereogenic unit). For this reason the intramolecular transfer of chirality is an impossibility. Transfer of chirality can only occur between two molecules and is quite uncommon. [An example is the enantioselective Meerwein-Ponndorf-Verley reduction of a ketone with a chiral alcohol.] What some authors refer to incorrectly as transfer of chirality is, in fact, retention of chirality in the course of modification of the stereogenic units present. 

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