Ethers alkyl chloromethylation

The above explains the key roles of (a) the nucleophilicity of the nucleophile (b) the substituent(s) (c) the polarity of the reaction medium and (d) the the bulkiness of the nucleophile, in determining the regio- and stereo-specificity of the reaction. The reaction of alkyl chloromethyl ethers with thiirane oxides to give sulfenic esters128 appears to be mechanistically analogous. 

A mechanism analogous in many ways to that of the acid-catalyzed ring opening reaction was advanced for the reaction of the thiirane oxide with alkyl chloromethyl ethers S . The first step is the displacement of the chloride by the sulfoxy oxygen (equation 24). In view of the above mechanistic interpretation, it is quite surprising that the parent thiirane oxide (16a) was found to be protonated on sulfur and not at oxygen in FSOjH-SbFfi at — 78 °C, according to NMR studies s . 

Caution. The sodium tetrahydroborate should be added slowly to prevent foaming of the reaction mixture from the reaction vessel. Alkyl chloromethyl ethers are potent carcinogens13 and should be handled and disposed of with appropriate precautions. 

Hydroxymethylation of carbonyl compounds.3 Alkyl chloromethyl ethers react in the presence of Sml2 (2 equiv.) with ketones in THF to give adducts in 50-80% yield. The reaction with aldehydes is conducted in tetraethylene glycol dimethyl ether, which suppresses pinacol reduction. Hydroxymethylation of carbonyl compounds can be effected by use of benzyl chloromethyl ether followed by hydrogenolysis of the adduct. 

Certain diethers of the type ROCHaCH OR have been prepared by adding alkyl halides to a solution of sodium in excess ethylene glycol monoalkyl ether, as in the preparation of ethylene glycol dimethyl ether (78%). Chloromethyl methyl ether and alcohols react to give an acetal derivative of formaldehyde, CHjOCHjOR the reaction is carried out in the presence of pyridine. Aromatic diethers such as 2-methoxydiphenyl ether have been prepared by the Ullmann procedure. ... 

Selective haloalkylation of aromatic compounds has also been achieved by employing alkyl haloalkyl ethers as the haloalkylating agents, as seen from equations (88) and (89). However, the use of chlo-romethyl ethers in chloromethylation (equation 89) is discouraged due to the carcinogenic nature of the ether substrate. As an alternative, chloromethylation reactions can also be carried out using paraformal-dehyde-HCl in the presence of ZnCh or SnCU as catalyst. ... 

A number of other miscellaneous systems that bear some relationship to Reissert compounds have also been reported but will not be covered in depth here. Thus, for example, the reaction of isoquinoline, potassium cyanide, and alkyl chloromethyl ethers give 116. A similar compound was also prepared from quinoline. Compounds of type 117 have been reported to undergo rearrangements similar to Reissert compounds. A... 

An interesting, different type of Grignard compound, the (alkoxymethyl)-magnesium chlorides, can be obtained from alkyl chloromethyl ethers. These products decompose very easily thus ... 

Phase transfer reaction of the conjugate base of the JV,iV,iV -trialkylsulphamides (345) in the presence of benzyl triethylammonium chloride with chloromethyl ethyl ether or chloromethyl alkylthioethers yields the N,iV-dialkyl-iV -alkyl-iV -ether and thioether sulphamides (341)365 (equation 117). 

MAJOR USES Lab reagent chloromethylation monitoring indicator for chloromethyl ether alkylating agent in manufacture of polymers research chemical intermediate in the synthesis of anionic exchange strong base resins of the quartemary ammonium type. 

Alkyl chloromethyl ethers react with thiiran 1-oxide to give sulphenic esters (26), probably by way of an intermediate sulphoxonium salt (27). Thiiran oxide in FSOsH-SbF at — 78 C was protonated at sulphur and not at oxygen, according to n.m.r. studies. ... 

Reactions of Enolates and Enolate Equivalents.—Several papers have appeared on the use of enolates released from silyl enol ethers by Lewis acids. Fleming reports the regiospecific alkylation of either the thermodynamic or the kinetic silyl enol ethers with chloromethyl phenyl sulphide in the presence of titanium(iv) chloride. Oxidative or reductive removal of the sulphur gives a-methylene- or a-methyl-ketones respectively (Scheme 69). ... 

The hydroxyl groups can be alkylated in the usual manner. Hydroxyalkyl ethers may be prepared with alkylene oxides and chloromethyl ethers by reaction with formaldehyde and hydrogen chloride (86). The terminal chlorides can be easily converted to additional ether groups. 

Alkylation. Ben2otrifluoride can also be alkylated, eg, chloromethyl methyl ether—chlorosulfonic acid forms 3-(trifluoromethyl)ben2yl chloride [705-29-3] (303,304), which can also be made from / -xylene by a chlorination—fluorination sequence (305). Exchange cyanation of this product in the presence of phase-transfer catalysts gives 3-(trifluoromethylphenyl)acetonitrile [2338-76-3] (304,305), a key intermediate to the herbicides flurtamone... 

Alkylation involving formaldehyde in the presence of hydrogen chloride is known as chloromethylation (eq. 3). The reagent may be a mixture of formalin and hydrochloric acid, paraformaldehyde and hydrochloric acid, a chloromethyl ether, or a formal. Zinc chloride is commonly employed as a catalyst, although many other Lewis acids can be used. Chloromethylation of sahcyhc acids yields primarily the 5-substituted product 5-chlotomethylsahcyhc acid [10192-87-7] (4). 

Etherification. The reaction of alkyl haUdes with sugar polyols in the presence of aqueous alkaline reagents generally results in partial etherification. Thus, a tetraaHyl ether is formed on reaction of D-mannitol with aHyl bromide in the presence of 20% sodium hydroxide at 75°C (124). Treatment of this partial ether with metallic sodium to form an alcoholate, followed by reaction with additional aHyl bromide, leads to hexaaHyl D-mannitol (125). Complete methylation of D-mannitol occurs, however, by the action of dimethyl sulfate and sodium hydroxide (126). A mixture of tetra- and pentabutyloxymethyl ethers of D-mannitol results from the action of butyl chloromethyl ether (127). Completely substituted trimethylsilyl derivatives of polyols, distillable in vacuo, are prepared by interaction with trim ethyl chi oro s il an e in the presence of pyridine (128). Hexavinylmannitol is obtained from D-mannitol and acetylene at 25.31 MPa (250 atm) and 160°C (129). 

Several chlorophyll derivatives have been prepared by electrophilic substitution, inter alia by formylation reactions. Adopting methods from corrin chemistry.50 alkylation with chloro-methyl methyl ether (caution toxic),32k chloromethyl methyl sulfide,51 and dichloromethyl methyl ether (caution toxic)52 in the presence of Lewis acids are the methods of choice to introduce carbon residues into the chlorin frame work. The compounds listed below have been prepared by these methods. 

Another route to enantiomcrically pure iron-acyl complexes depends on a resolution of diastereomeric substituted iron-alkyl complexes16,17. Reaction of enantiomerically pure chloromethyl menthyl ether (6) with the anion of 5 provides the menthyloxymethyl complex 7. Photolysis of 7 in the presence of triphenylphosphane induces migratory insertion of carbon monoxide to provide a racemic mixture of the diastereomeric phosphane-substituted menthyloxymethyl complexes (-)-(/ )-8 and ( + )-( )-8 which are resolved by fractional crystallization. Treatment of either diastereomer (—)-(/J)-8 or ( I )-(.V)-8 with gaseous hydrogen chloride (see also Houben-Weyl, Vol 13/9a, p437) affords the enantiomeric chloromethyl complexes (-)-(R)-9 or (+ )-(S)-9 without epimerization of the iron center. 

The title compound has also been prepared by alkylations of (tributylstannyl)methanol with chloromethyl methyl ether (55% overall yield from paraformaldehyde) Sawyer, J. S. Kucerovy, A. Macdonald, T, L. McGarvey, G. J. J. Am. Chem. Soc. 1988, 110, 842. 

Methoxymethylation of alcohols is generally achieved through alkylation with chloromethyl methyl ether. The procedure described here for the preparation of Bu3SnCH20CH20CH3 avoids the use of the highly toxic chloromethyl ether by employing an acid-catalyzed acetal exchange reaction with dimethoxymethane for the... 

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