The Acetoxy group, abbreviated AcO or OAc, is a chemicalfunctional group of the structure CH3-C(=O)-O-. It differs from the acetyl group CH3-C(=O)- by the presence of one 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).
It must be noted that 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.
- Anhydrous base such as sodium methoxide in methanol. Very useful when a methyl ester of a carboxylic acid is also present in the molecule, as it will not hydrolyze it like an aqueous base would. (Same also holds with an ethoxide in ethanol with acetate esters)
