1.16 in ochem book

[Emily Wang 1H]

The answer says 2-isopropyl-1,1-dimethylcyclopentane. How do we know to use IUPAC or common naming? If we were to do IUPAC, would it be 1-methyl-2-ethyl-1,1-dimethyl-cyclopentane?

[Jerry Wang 1L]

Both IUPAC and common naming are accepted according to Lavelle. Common naming is more convenient compared to IUPAC because it is shorter (as you will see in the following). For example, the strict IUPAC naming of the compound you have provided will be 1,1-dimethyl-2-(1-methylethyl)-cyclopentane. (Feel free to correct me if I am wrong) For more information about IUPAC vs. common naming, see pg. 9.