Von Baeyer system

Extension and revision of the von Baeyer system for naming polycyclic compounds (including bicyclic compounds), lUPAC recommendations for naming heterocycles 99PAC513. 

Extended von Baeyer System for Bridged Structures (IUPAC Rules... 

Two methods are available for naming bridged cyclic skeletons. One (the von Baeyer system see the following section, 5) is particularly suitable for naming predominantly saturated skeletons the other, to be described now, is appropriate for predominantly unsaturated skeletons and involves citing the bridge as a prefix to a fusion name. 

Replacement principles can be applied satisfactorily to all these systems in order to name heterocycles. Indeed, this is the only way in which the von Baeyer system and the spiro method 6a, i (i.e., the systems of type II see above) can be used in the heterocyclic series. However, as explained in Section II, B, 1, b, replacement nomenclature has not previously been applied extensively in other areas, although it has been used to a limited extent for fused skeletons. It is to be hoped that its use will increase. 

BRIDGED HETEROCYCLIC SYSTEMS Rule B-14. Extension of the von Baeyer System... 

Because of the cumbersome and usually exasperating nature of the von Baeyer system of formal nomenclature,422 especially when applied to complex polycyclic systems, a colloquial nomenclature has been developed for the higher poly-quinanes.415,42 The system applies only to polycondensed, fused, equal-size ringed molecules (no spiro fusions) and states the total number of carbon atoms, the number of basic rings, and their size. An indicator of ring juncture stereochemistry is also required on occasion, a symmetry designation must be added. Thus, all-cis-484 is (Q-C 14-tetraquinane and all-cis-485 is(C2)-Ci4-tetraquinane. 

Replacement nomenclature is also used for some heterocyclic systems, including von Baeyer systems (see Chapter 4), large rings (>10 members) and some spiro compounds. 

Many bridged ring systems are named by the von Baeyer system. Von Baeyer names are used mostly for bridged ring systems and occasionally for nonbridged ring systems. Examples of von Baeyer names are bicyclo[3.2.1]octane and tricyclo[7.4.1.0 ]tetradecane. 

On insertion of double bonds, especially more than one such bond, into such systems one rapidly encounters borderline situations which in many cases suggest that it might be more reasonable to apply an alternative naming method. While the following compounds, both valence isomers of benzene (as is prismane above), can be named clearly and unambiguously by the von Baeyer system,... 

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