Ketones are commonly named by listing the alkyl groups in alphabetical order, followed by ketone,
such as ethylmethylketone. Acetone is the smallest possible ketone molecule, and it defies
traditional naming conventions because it has three rather than two carbons (acet–, like eth–
generally refers to two carbons). Figure 1.9 includes IUPAC and common names for a number of
ketones.
Figure 1.9. Naming Ketones
Common names are included in parentheses.MCAT EXPERTISE
As is the case for alcohols, it is important to know both the common names and IUPAC
names for common aldehydes and ketones. Make sure that you know what formaldehyde,
acetaldehyde, and acetone are!In a more complex molecule with a higher-priority group that takes precedence over the carbonyl,
we name aldehydes and ketones as substituents, using the prefix oxo–. This is in reference to the
carbonyl oxygen and applies for both ketones and aldehydes. Sometimes ketones may also be
indicated with the prefix keto–.