Benzyl bromide sulfoxide

Benzyl bromide is converted into benzaldehyde by heating in dimethyl sulfoxide. Propose a structure for the intermediate, and show the mechanisms of the two steps in the reaction. 

In the reaction of 88 with /(-phenethyl bromide, l-phenethyl-3-phenylpropyl methyl sulfoxide and bis-3-phenylpropyl sulfoxide, besides 3-phenylpropyl methyl sulfoxide are obtained118. Sulfoxides, bearing a /1-hydrogen to the sulfmyl function, give olefins upon thermolysis. Utilizing this reaction, Trost and Bridges120 alkylated benzyl phenyl sulfoxide, 3,4-methylenedioxybenzyl phenyl sulfoxide, phenylthiomethyl phenyl sulfoxide, phenylsulfinylmethyl phenyl sulfoxide and cyanomethyl phenyl sulfoxide with alkyl, allyl and benzyl halides and subjected these sulfoxides to thermolysis, obtaining olefins in one-pot processes. 

Benzyl bromide, Molecular sieve, 2735 tert-Butyl hydroperoxide. Molecular sieves, 4477 Mercmy(II) perchlorate 6 (or 4)dimethyl sulfoxide, 4079... 

Heterocyclic amines have also been used as phase transfer catalysts. However, because these amines quaternize easily, the question is whether the operative catalyst is the tertiary amine or the quaternary ammonium salt formed in situ Furukawa et al.286 have shown that a methyl 2-pyridyl sulfoxide may be used as a phase transfer catalyst and promote substitution reactions between lithium chloride or sodium cyanide and benzyl bromide. According to the authors, the catalyst behaves as a cation complexer and not as a quaternary ammonium salt formed in situ by a Menschutkin reaction. 

Benzyl Bromide — Sodium Hydride — fV,/V-Dimethy)fonnamide or Dimethyl Sulfoxide... 

Examples of molecular sieve incidents other than the subentries Benzyl bromide, Molecular sieve, 2731 terf-Butyl hydroperoxide, Molecular sieves, 1692 Mercury(II) perchlorate. 6 (or 4)dimethyl sulfoxide, 4073 Nitromethane, Molecular sieve, 0455 Oxygen difluoride, Adsorbents, 4311 1,1,1-Trichloroethane, 0737... 

Sn2 displacement occurs when the negatively charged oxygen of dimethyl sulfoxide attacks the benzylic carbon of benzyl bromide, displacing Br-... 

The reactions between a-metalloalkyl sulfoxides and electrophiles have been extensively studied. Although alkylations of the sodium or potassium salts of dialkyl sulfoxides are not always very efficient since a,a -dialkylated sulfoxides are often produced (or stilbene in the case of methyl-sulfinyl carbanion and benzyl bromide ), those employing the lithioalkyl aryl sulfoxides work more efficiently with alkyl or allyl halides " and with epoxides. " " Typical examples of these alkylations, allylations and hydroxyalkylations (from epoxides) are illustrated in Scheme 86. 

Polymers, with [//] = 0.30—0.56 dl/g, containing methyl sulfonyl groups have been synthesized by copolymerization of methyl-4-vinylphenyl sulfoxide with styrene [92]. These copolymers are soluble in toluene but are insoluble in water. Their catalytic activity has been studied in Sf 2-type reactions of alkyl halides with different nucleophiles in water-toluene solutions at 100°C for 20 h. The copolymers effectively catalyze two-phase reactions of octyl bromide with KSCN, NaSCN and KI and of butyl bromide with NaOPh and NaSPh with a 11-78% yield of respective reaction products. These reactions, however, are not catalyzed by DMSO, methylphenyl-sulfoxide and benzyl methyl sulfoxide. The copolymer catalytic activity is higher than that of the monomer analogues and increases with an increment in the number of styrene units in the copolymer. These copolymeric catalysts are easily extracted from the reaction medium. The influence of the hydrophobic environment of active centers on the catalytic activity of polymeric catalysts has already been discussed. 

Sulfoxide 6 has been prepared by treating l,2 5,6-dianhydro-3,4-0-isopro-pylidene-D-mannitol successively with the appropriate thiol-potassium carbonate, benzyl bromide-sodium hydride, MCPBA then aqueous acetic acid. Substitution of MCPBA by meta-periodic acid led to the formation of sulfone 7. The compounds were tested as potential inhibitors of HIV-1 protease. ... 

Independently, Okamura and colleagues generated racemic a-lithiated-(x,P-unsaturated sulfoxides in the same way as Posner s group and reported their reactions with methyl iodide, carbonyl compounds, and epoxides [48.49]. They also noted the configurational instability of such intermediates. Alkylation of the intermediates using butyl iodide or benzyl bromide gave low yields of products. 

Methyl methylthiomethyl sulfoxide treated with NaH in tetrahydrofuran, benzyl bromide added, and stirred below 40° phenylacetaldehyde dimethyl mercaptal S-oxide. Y 92%. - The product can be converted to an aldehyde by acid treatment, preferably via the diethyl acetal obtainable in the presence of ethyl orthoformate. The method is suitable for the prepn. of labile aldehydes. F. e. s. K. Ogura and G. Tsuchihashi, Tetrah. Let. 1971, 3151 aldehydes from halides via s-trithianes cf. D. Seebadi and A. K. Beck, Org. Synth. 51, 39 (1971) via thiazoles cf. L. J. Altman and S. L. Richheimer, Tetrah. Let. 1971, 4709. 

Kornblum aldehyde synthesis. 1-Iodoheptane added at 0-5° to a soln. of Ag-tosylate in acetonitrile protected from light, allowed to come to room temp, overnight, the resulting crude tosylate added at 150° to a freshly prepared mixture of NaHGOg and dimethyl sulfoxide through which Ng is passed, and cooled rapidly to room temp, after 3 min. at 150°-> n-heptaldehyde. Y 70% as the 2,4-dinitrophenylhydrazone.—Similarly at 100° during 5 min. p-Bromo-benzyl bromide p-bromobenzaldehyde. Y 76% as the 2,4-dinitrophenylhydrazone. F. e. s. N. Kornblum, W. J. Jones, and G. J. Anderson, Am. Soc. 81, 4113 (1959). 

DMSO or other sulfoxides react with trimethylchlorosilanes (TCS) 14 or trimefhylsilyl bromide 16, via 789, to give the Sila-Pummerer product 1275. Rearrangement of 789 and further reaction with TCS 14 affords, with elimination of HMDSO 7 and via 1276 and 1277, methanesulfenyl chloride 1278, which is also accessible by chlorination of dimethyldisulfide, by treatment of DMSO with Me2SiCl2 48, with formation of silicon oil 56, or by reaction of DMSO with oxalyl chloride, whereupon CO and CO2 is evolved (cf also Section 8.2.2). On heating equimolar amounts of primary or secondary alcohols with DMSO and TCS 14 in benzene, formaldehyde acetals are formed in 76-96% yield [67]. Thus reaction of -butanol with DMSO and TCS 14 gives, via intermediate 1275 and the mixed acetal 1279, formaldehyde di-n-butyl acetal 1280 in 81% yield and methyl mercaptan (Scheme 8.26). Most importantly, use of DMSO-Dg furnishes acetals in which the 0,0 -methylene group is deuter-ated. Benzyl alcohol, however, affords, under these reaction conditions, 93% diben-zyl ether 1817 and no acetal [67]. 

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