In organic chemistry, a methoxymethyl ether is a functional group with the formula ROCH2OCH3, 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.[1][2] 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[3] 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[4] and by the acid-catalyzed reaction of alcohols with dimethoxymethane.[5]
Deprotection
The MOM and the MEM protecting groups can be cleaved with a range of Lewis and Bronsted acids.[6]
^William F. Bailey, Matthew W. Carson, Lyn M. J. Zarcone (1998). "Selective Protection of 1,3-Diols at the More Hindered Hydroxy Group: 3-(Methoxymethoxy)-1-Butanol". Organic Syntheses. 75: 177. doi:10.15227/orgsyn.075.0177.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Kohei Tamao, Yoshiki Nakagawa, and Yoshihiko Ito (1996). "Regio- AND Stereoselective Intramolecular Hydrosilylation of a-Hydroxy Enol Ethers: 2,3-syn-2-Methoxymethoxy-1,3-nonanediol". Organic Syntheses. 73: 94. doi:10.15227/orgsyn.073.0094.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Amano, Seiji; Takemura, Noriaki; Ohtsuka, Masami; Ogawa, Seiichiro; Chida, Noritaka (1999-03-26). "Total synthesis of paniculide A from d-glucose". Tetrahedron. 55 (13): 3855–3870. doi:10.1016/S0040-4020(99)00096-4.
