Chloromethyl with alcoholates

The reaction of tetrachlorocyclopropene with di-isopropylphosphine gives the cyclopropenylphosphonium salt (120). Chloromethyl isocyanate reacts with tertiary arylphosphines to give the salts (121), which, on treatment with alcohols, form (122). ... 

Alternatively, these heterocycles (e.g., 157) can be prepared by the reaction of dimethyl-(chloromethyl)allylsilane (156) with alcoholic KSH (Equation (30)) <83J0M(243)271, 83ZOB2404>. A similar cyclization can be effected by the photoinduced addition of H2S to the vinyl congener of (156) <82ZOB712>. 

The alkyl chloride known as methyl chloromethyl ether, MeOCH2Cl, reacts very well with alcohols to form ethers. Being a primary alkyl chloride, you might think that its reactions would follow an 5 2 mechanism, but in fact it has characteristic S l reactivity. As usuai, the reason for its preference for the S l mechanism is its ability to form a stabilized carbocation. Loss of the chloride ion is assisted by the adjacent lone pair, and we can draw the resulting cation either as an oxonium ion or as a carbocation. 

Oxathietan 1,1-dioxide (130) reacts with alcohols to give (2-fluorosulphonyl)-carboxylic esters, and with BFj and EtjN to give fluorosulphonyl(trifluoro-methyl)keten. The latter reaction is more efficient if the ring is first opened with KF and HF. Chloral cyclo-adds to sulphenes to give yff-sultones. 4-Tri-chloromethyl-l,2-oxathietan 2,2-dioxide reacts with primary and secondary amines to give y5-hydroxy-sulphonamides. ... 

On reaction with f oiinaldehyde jwid hydrogen chloride, niercaptans give alpha-chloromethyl thioetliers analogous to the alpha-chloi-omethyl ethers obtained with alcohols. 

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). 

Benzyl chloride [(chloromethyl)henzene, a-chlorotoluene], CgH CH2Cl, is a colorless Hquid with a very pungent odor. Its vapors are irritating to the eyes and mucous membranes, and it is classified as a powerfljl lacrimator. The physical properties of pure benzyl chloride are given in Table 2 (2—7). Benzyl chloride is insoluble in cold water, but decomposes slowly in hot water to benzyl alcohol. It is miscible in all proportions at room temperature with most organic solvents. The flash point of benzyl chloride is 67°C (closed cup) 74°C (open cup) autoignition temperature is 585°C lower flammability limit 1.1% by volume in air. Its volume coefficient of expansion is 9.72 x. ... 

Dimroth rearrangement, 5, 438 Imidazolium chloride, 4-chloromethyl-reaction with poly(vinyl alcohol), 1, 306 Imidazolium chloride, 2,4,5-tri(diethylamino)-reduction, 5, 415 Imidazolium complexes, 7, 746... 

The polymer-bound catalysts A-C. (Table 31) are prepared by reaction of the corresponding amino alcohols with partially chloromethylated 1 -2% cross-linked polystyrene. In the case of A, the enantioselectivity of the addition of dialkylzincs to aldehydes is higher than with the corresponding monomeric ephedrine derivatives (vide supra). Interesting insights into the mechanism of the alkylation of aldehydes by dialkylzinc reagents can be obtained from the experi-... 

This procedure illustrates a general method for the stereoselective synthesis of ( P)-disubstitnted alkenyl alcohols. The reductive elimination of cyclic /3-halo-ethers with metals was first introduced by Paul3 and one example, the conversion of tetrahydrofurfuryl chloride [2-(chloromethyl)tetrahydrofuran] to 4-penten-l-ol, is described in an earlier volume of this series.4 In 1947 Paul and Riobe5 prepared 4-nonen-l-ol by this method, and the general method has subsequently been applied to obtain alkenyl alcohols with other substitution patterns.2,6-8 (I )-4-Hexen-l-ol has been prepared by this method9 and in lower yield by an analogous reaction with 3-bromo-2-methyltetra-hydropyran.10... 

Naphthalene dioxygenase from P. putida strain FI is able to oxidize a number of haloge-nated ethenes, propenes, and butenes, and d5 -hept-2-ene and cis-oct-2-ene (Lange and Wackett 1997). Alkenes with halogen and methyl substituents at double bonds form allyl alcohols, whereas those with only alkyl or chloromethyl groups form diols. 

From chloromethyl or bromomethyl aromatic compounds by heating with hexamethylenetetramine (hexamine) in aqueous alcohol or aqueous ac ic acid. A quaternary ammonium compound is formed, which yields the aldehyde upon treatmait with water in the presence of hexamine for example... 

Halide ions will also act as nucleophiles towards aldehydes under acid catalysis, but the resultant, for example, 1,1-hydroxychloro compound (35) is highly unstable, the equilibrium lying over in favour of starting material. With HC1 in solution in an alcohol, ROH, the equilibrium is more favourable, and 1,1-alkoxychloro compounds may be prepared, e.g. 1-chloro-l-methoxymethane (36, a-chloromethyl ether ) from CH20 and MeOH (cf. acetal formation, p. 209), provided the reaction mixture is neutralised before isolation is attempted ... 

Ye et al. reported that the reduction of 2,4-dichlorophenyl-2-chloroethanone 1 with potassium borohydride in dimethylformamide to give 90% a-chloromethyl-2,4-dichlorobenzyl alcohol 2. Alkylation of imidazole with compound 2 in dimethyl formamide in the presence of sodium hydroxide and triethylbenzyl ammonium chloride, gave l-(2,4-dichlorophenyl-2-imidazolyl)ethanol 3 and etherification of 3 with 2,4-dichlorobenzyl chloride under the same condition, 62% yield of miconazole [9]. 

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... 

In 1983, Prasad et al.12 first reported the condensation of chloromethyl polystyrene with /V-hydroxyphthalimide to give the ester, hydrazinolysis of which yielded the desired resin-bound hydroxylamine. However, the sole purpose of this reagent was to react with, and hence extract ketones from, a complex steroidal mixture, and its use for the solid-phase synthesis of hydroxamic acids was not explored. Recently, the exploitation of the above solid-phase approach for the synthesis of hydroxamic acids was independently reported by three groups,7-9 all of which differ only in the method for the initial anchoring of TV-hydroxyphtha-limide to an 4-alkoxybenzyl alcohol functionalized polystyrene or trityl chloride polystyrene. Subsequent /V-deprotection was... 

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