How would the "-COOCl" functional group be named?

I had this question that has been bouncing around for over 2 years.


Basically, I imagined this molecule:


[![enter image description here](https://i.stack.imgur.com/mgdOJm.png)](https://i.stack.imgur.com/mgdOJ.png)


This molecule, as far as my former (and current) knowledge of nomenclature goes, couldn't be named by me. At first, when I was in about 11th grade, I used to call it *ethanoyl chloride*, but that's $\ce{CH3COCl}$, not $\ce{CH3COOCl}$. I then thought of *chlorine ethanoate*, but that's ridiculous too, since chlorine can accomodate the negative charge way better than what ethanoate can.


I looked up a while, and I found out that the $\ce{-OCl}$ group is called a hypochlorite group, that gave rise to my third guess *ethanoyl hypochlorite*. However, I am not very sure about that either, since ethanoic acid isn't called ethanoyl hydroxide, and methylmethanoate isn't called methanoyl methoxide.


So, **what would the "-COOCl" group be called?**




Acetyl hypochlorite CAS 758-11-2


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One could be tempted to name this compound as acid halide of a peroxycarboxylic acid (here: ethaneperoxoic acid). However, the compound could also be named as anhydride of acetic acid and hypochlorous acid. Note that anhydrides have a higher priority in the seniority order for classes than acid halides.


And indeed, the current version of *[Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book)](http://dx.doi.org/10.1039/9781849733069-fp001)*, mentions that hypochlorous acid forms anhydrides such as benzoic hypochlorous anhydride. The rule for the formation of such names can be found in Subsection P-67.1.3.3:



> 
> **P-67.1.3.3** Anhydrides of mononuclear noncarbon oxoacids
> 
> 
> Neutral anhydrides formed between acids named by suffixes and mononuclear noncarbon oxoacids described in P-67.1.1 are named in the same way as described for anhydrides derived from carboxylic and the sulfur acids named by suffixes (see P-65.7). The names of the acids are cited in alphabetical order followed by the class name ‘anhydride’ prefixed by a numerical term indicating the number of anhydride linkages (the numerical prefix mono is not used); such names lead to preferred IUPAC names. (…) Halogen oxoacids form anhydrides with carboxylic and the sulfur acids expressed by suffixes.  
> 
> (…)
> 
> 
> 


Therefore, the preferred name for the compound that is given in the question is **acetic hypochlorous anhydride.**


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