In organic chemistry, a methoxymethyl ether is a functional group with the formula , abbreviated MOM. The group is usually derived from chloromethyl methyl ether, a kind of chloroalkyl ether which is, like its congeners, often employed in organic synthesis to protect alcohols. Closely related to MOM ethers are methoxyethoxymethoxy (MEM) protecting groups, introduced using 2-methoxyethoxymethyl chloride. The MEM protecting groups are more easily installed and more easily removed.
Protection Typically, the alcohol is protected by addition of the chloromethyl reagent followed by deprotonation with a non-nucleophilic base such as N,N-diisopropylethylamine (DIPEA) in dichloromethane.
Although not relevant to protecting groups, MOM groups are installed by reaction of chloromethyl ethers with methoxide and by the acid-catalyzed reaction of alcohols with dimethoxymethane.
Deprotection
The MOM and the MEM protecting groups can be cleaved with a range of Lewis and Brønsted acids.
Safety Chloromethyl methyl ether and chloromethoxyethoxymethane, like other chloroalkyl ethers, are strong alkylating agents with attendant dangers. These compounds are human carcinogen.Bis(chloromethyl) Ether and Technical-Grade Chloromethyl Methyl Ether CAS Nos. 542-88-1 and 107-30-2, Report on carcinogens, Eleventh edition
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