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Chloroalkyl ether

Chloroalkyl ethers are a class of organic compounds with the general structure R-O-(CH₂)_n-Cl, characterized as an ether connected to a chloromethyl group via a alkane chain

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Chloromethyl methyl ether (CMME) is an ether with the formula C H₃O C H₂Cl. It is used as an alkylating agent and industrial solvent to manufacture dodecylbenzyl chloride, water repellents, ion-exchange resins, polymers, and as a chloromethylation reagent. It is a known human carcinogen ^[1]. In organic synthesis the compound is used for the introduction of the methoxymethyl(MOM) protecting group.

Closely related compounds of industrial importance are bis(chloromethyl ether) (BCME) (closely related to chemical weapon sulfur mustard) ^[2] and benzyl chloromethyl ether.

Chloromethyl ether	R	Molar mass	CAS number	Boiling point °C
benzyl chloromethyl ether	Benzyl	121.93	98-80-6	102 14 mm Hg
methyl chloromethyl ether	Methyl	80.51	107-30-2	55-57
bischloromethyl ether		114.96	542-88-1	106
Representative chloroalkyl ethers ^[3]

MOM ethers

Methyl chloromethyl ether (often abbreviated MOMCl) is used as a protecting group for alcohols. The product formed is a MOM ether. A base such as N,N-diisopropylethylamine is a requirement.

The MOM group can be removed by application of dilute acid.

An example is the protection of a phenol group ^[4]:

With a benzyl group the protective group becomes a BOM-ether. See also the closely related methylthiomethyl ethers.

References

^ bis(Chloromethyl) Ether and Technical-Grade Chloromethyl Methyl Ether CAS Nos. 542-88-1 and 107-30-2 Report on carcinogens, eleventh edition
^ Bis(Chloromethyl) ether Safety Data Sheet Division of Occupational Health and Safety US National Institutes of Health LInk
^ www.sigmaaldrich.com
^ Enantioselective total synthesis of (2)-heliannuol A Hidetoshi Kishuku, Mitsuru Shindo and Kozo Shishido Chem. Commun., 2003, 350–351 Article link