Cahn-Ingold-Prelog-System

A subrule of the Cahn-Ingold-Prelog system specifies that higher mass number takes prece dence over lower when distinguishing between isotopes... 

Sequence rule (Section 7 6) Foundation of the Cahn-Ingold-Prelog system It is a procedure for ranking substituents on the basis of atomic number... 

The system that has replaced the dl system is the Cahn-Ingold Prelog system, in which the four groups on an asymmetric carbon are ranked according to a set of sequence rules. For our purposes, we confine ourselves to only a few of these rules, which are sufficient to deal with the vast majority of chiral compounds. 

TABLE 4.1 How Four Common Groups Are Il-eated in the Cahn-Ingold-Prelog System... 

The Cahn-Ingold-Prelog system is unambiguous and easily applicable in most cases. Whether to call an enantiomer (R) or (S) does not depend on correlations, but the configuration must be known before the system can be applied, and this does depend on correlations. The Cahn-Ingold-Prelog system has also been extended to chiral compounds that do not contain chiral atoms.A series of new rules have been proposed to address the few cases where the rules can be ambiguous, as in cyclophanes and other systems. ... 

Additions. For simple 1,2-additions, the names of both addends are given followed by the suffix addition . The addends are named in order of priority in the Cahn-Ingold-Prelog system (p. 139), the lower ranking addend coming first. Multivalent addition is indicated by biaddition , and so on. 

FIGURE 1.1 Chemical and stereochemical nature of amino acids. Substituents in (a) and (b) are on opposite sides of the plane N-Ca-C, the bold bond being above the plane. Interchange of any two substituents in (a) changes the configuration. For the Cahn-Ingold-Prelog system of nomenclature, the order of preference NH2 > COOH > R2 relative to H is anticlockwise in (a) = (S) and clockwise in (c) = (R). 

The DL-system is in common use with respect to amino acids and sugars, but the Cahn-Ingold-Prelog system (the RS-sysitm) is more systematic and should be used. 

The literature is replete with reports failing to specify the stereochemistry of certain reactions, and one must often infer the enantiomer. See Configuration Cahn-Ingold-Prelog System Corn Rule Diastereomers Enantiomers (R/S)-Convention... 

R und S symbolisieren die (R)- bzw. (S)-Form des Produktes. Hier und im folgenden wird die Chiralitat (Konfiguration) in der Regel nach dem Cahn-Ingold-Prelog-System (57, 58) gekennzeichnet. 

There are two systems to designate configuration of enantiomers the D and L system, and the (R) and (S) system (also known as the Cahn-Ingold-Prelog system). 

Following the Cahn-Ingold-Prelog system, it is now possible to draw the structures of (i )- and (5)-enantiomers of various chiral molecules, for example 2,3-dihydroxypropanoic acid, where the priorities are 1 = OH, 2 = COOH, 3 = CH2OH and 4 = H. 

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