In organic chemistry, the acetoxy group (abbr. AcO or OAc; IUPAC name: acetyloxy), is a functional group with the formula −OCOCH3 and the structure −O−C(=O)−CH3. As the -oxy suffix implies, it differs from the acetyl group (−C(=O)−CH3) by the presence of an additional oxygen atom. The name acetoxy is the short form of acetyl-oxy.
An acetoxy group may be used as a protection for an alcohol functionality in a synthetic route although the protecting group itself is called an acetyl group.
There are several options of introducing an acetoxy functionality in a molecule from an alcohol (in effect protecting the alcohol by acetylation):
An alcohol is not a particularly strong nucleophile and, when present, more powerful nucleophiles like amines will react with the above-mentioned reagents in preference to the alcohol.
For deprotection (regeneration of the alcohol)
The systematic name 'acetyloxy' is preferred to the contracted name 'acetoxy' that may be used in general nomenclature.