Ethyl methyl ether, synthesis from alkyl

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

Aromatic and aliphatic amino ethers have been synthesized by this method. An example of the formation of a cyano ether is the preparation of p-cyano benzyl methyl ether from the substituted benzyl bromide and sodium methoxide (84%). Also, certain aryloxyacetonitriles, AtOCHjCN, are made by the condensation of chloroacetonitrile with sodium phenoxides in a solution of methyl ethyl ketone containing a small amount of sodium iodide (70-80%). Aromatic nitro ethers, like o- and p-nitrodiphenyl ether, have been prepared by the Ullmann procedure (84%). The synthesis of alkyl p-nitrophenyl ethers has also been accomplished with good yields (55-92%). ... 

The following, inter alia, can also be obtained by the Henry synthesis chlo-romethyl methyl ether from formaldehyde,518,993 paraformaldehyde,994 or s-trioxan 995 1-chloroethyl ethyl ether from paraldehyde 531,996 and similarly 1-bromo-992,997 and 1-iodo-alkyl ethers.993... 

This reaction is similar to the Williamson synthesis of ethers (method 115). Otthofotmates in which the alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and isoamyl have been prepared from chloroform. The yield of ethyl orthoformate is 45%. Mixed esters are obtained from a mixture of sodium alkoxides and chloroform. Benzotrichloride, C,HjCClj, is converted to methyl orthobenzoate in 86% yield by sodium methoxide in methanol, ... 

Preparation.— The classical Williamson route to ethers from alcohols and alkyl halides can lead to racemization of chiral centres carrying hydrogen and situated a-or /8- to the alcohol OH groups. A new synthesis of methyl and ethyl ethers that avoids such problems uses trialkyloxonium tetrafluoroborates as the alkylating agents [equation (14)] in the presence of a non-nucleophilic base to remove the acid... 

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