common-names-geneva-system-6

Nomenclature of bicyclic compounds

We name compounds containing 2 fused or bridged rings as bicyclo alkanes and we use the name of the alkane corresponding to the total number of carbon atoms as the base name. The carbon atoms common to both the rings are called bridgeheads, and each bond, or chain of atoms connecting the bridgehead atoms, is called a bridge.

In between the words bicyclo and alkane we interpose in the name an expression in the square brackets that denotes the number of carbon atoms in each bridge (in descending order). For example,

If substitutions are present, we number the bridged ring system beginning at one bridgehead, proceeding first along the longest bridge to the other bridgehead, then along the next longest bridge back to the first bridgehead. The shortest bridge in numbered last.

Polycyclic Systems

(a) The main ring shall inculcate as many aspossible carbon atoms, two of which must work as bridgeheads for the main bridge system.