Acetoxy group

 ( Functional Groups ) 

In organic chemistry, the acetoxy group (abbr. AcO– or –OAc; IUPAC name: acetyloxy

), is a functional group with the Chemical formula and the structure . As the -oxy suffix implies, it differs from the acetyl group () by the presence of an additional oxygen atom. The name acetoxy is the short form of acetyl-oxy.

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Functionality 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.

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Alcohol protection There are several options of introducing an acetoxy functionality in a molecule from an alcohol (in effect protecting the alcohol by acetylation):

• Acetyl halide, such as acetyl chloride in the presence of a base like triethylamine
  Robert J. Ouellette (2025). 9780128128381 . ISBN 9780128128381
• Activated ester form of acetic acid, such as a N-hydroxysuccinimide ester, although this is not advisable due to higher costs and difficulties.
• Acetic anhydride in the presence of base with a catalyst such as pyridine with a bit of DMAP added.

An alcohol is not a particularly strong nucleophile and, when present, more powerful nucleophiles like will react with the above-mentioned reagents in preference to the alcohol.

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Alcohol deprotection For deprotection (regeneration of the alcohol)

• Aqueous base (pH >9)
  Krzysztof Matyjaszewski (2025). 9780080878621, Elsevier Science. . ISBN 9780080878621
• Aqueous acid (pH <2), may have to be heated
• 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 ethyl esters)

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See also

• Acetate #Esters
• Acetyl group
• Acetylation

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