SPIRO COMPOUNDS

SP-1 Compounds with only monocyclic ring components
SP-1.1 Monospiro hydrocarbons with two monocyclic rings are named by the prefix spiro before a von Baeyer descriptor (indicating the numbers of carbon atoms linked to the spiro atom in each ring in ascending order and separated by a full stop) placed in square brackets and then the name of the parent hydrocarbon indicating the total number of skeletal atoms e.g. spiro[4.4]nonane.
SP-1.2 Monospiro hydrocarbons with two monocyclic rings are numbered consecutively starting in the smaller ring at an atom next to the spiro atom, proceeding around the smaller ring back to the spiro atom and then round the second ring.
Example:


spiro[4.5]decane
not spiro[5.4]decane

SP-1.3 Heteroatoms are indicated by replacement prefixes (rules B-4.2, B-6.1, 5 and rules R-1.2.2.1 and R-9.3, ref 6) and unsaturation is indicated in the usual way (rule A-11.3, ; R-3.1.1, ) by the endings ene, diene, etc.

Examples:


8-azaspiro[4.5]dec-2-ene

spiro[4.4]nona-2,7-diene

3,9-diazaspiro[5.5]undecane
SP-1.4 Unbranched polyspiro hydrocarbons composed of only monocyclic rings are named using dispiro-, trispiro-, etc. indicating the total number of spiro atoms present and the name of the parent hydrocarbon corresponding