The compound whose name is to be determined is the following.
As you can see, we have two options for the parent hydride.
- The butane chain which has 4 substituents - two methyl groups, one bromine atom, and one phenyl group.
- The benzene ring which has one substituent.
Now, from Section P-52.2.8 of the Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013, IUPAC Blue book, we have,
P-52.2.8 Selection between a ring and a chain as parent hydride
Within the same heteroatom class and for the same number of characteristic groups cited as the principal characteristic group, a ring is always selected as the parent hydride to construct a preferred IUPAC name. In general nomenclature, a ring or a chain can be the parent hydride (see P-126.96.36.199).
Therefore, we need to choose option for the preferred IUPAC name, therefore we now need to find the one substituent attached to the benzene ring.
In order to find the right numbering of locants, we use Section P-14.
When several structural features appear in cyclic and acylic compounds, low locants are assigned to them in the following decreasing order of seniority.
(c) principal characteristic groups and free valences (suffixes);
(f) detachable alphabetized prefixes, all considered together in a series of increasing numerical order;
(g) lowest locants for the substituent cited first as a prefix in the name;
Note that Rule f takes precedence over Rule g.
The lowest set of locants is defined as the set that, when compared term by term with other locant sets, each cited in order of increasing value, has the lowest term at the first point of difference (…)
Therefore in this case, we have two possible locant sets:
- 4-bromo-2,2-dimethylbut-4-yl [2,2,4]
- 1-bromo-3,3-dimethylbut-1-yl [1,1,3]
We can remove the '-1-' in option 2 using section P-29.2, which states:
P-29.2 GENERAL METHODOLOGY FOR NAMING SUBSTITUENT GROUPS
(1) The suffixes ‘yl’, ‘ylidene’, and ‘ylidyne’ replace the ending ‘ane’ of the parent hydride name. The atom with the free valence terminates a chain and always has the locant ‘1’, which is omitted from the name. This
method is recommended primarily for saturated acyclic and monocyclic hydrocarbon substituent groups and for the mononuclear hydrides of silicon, germanium, tin, and lead. Substituent groups formed by this method are referred to as ‘alkyl-type substituent groups’;
By section P-14.4 (c), option 2 is preferred, therefore the PIN of the compound becomes (1-bromo-3,3-dimethylbutyl)benzene