Dimethyl sulfoxide aldehydes

Dimethyl sulfoxide Aldehydes and carboxylic acids from ozonides... 

Synthesis of aldehydes from pnmary alkyl halides or tosylales, using dimethyl sulfoxide (OMSO). 

The S >ern oxidation is a preparatively important reaction which allows for the oxidation of primary and secondary alcohols 1 to aldehydes and ketones 2, respectively, under mild conditions, using activated dimethyl sulfoxide (DMSO) as the oxidizing agent. 

The classical procedure for the Wolff-Kishner reduction—i.e. the decomposition of the hydrazone in an autoclave at 200 °C—has been replaced almost completely by the modified procedure after Huang-Minlon The isolation of the intermediate is not necessary with this variant instead the aldehyde or ketone is heated with excess hydrazine hydrate in diethyleneglycol as solvent and in the presence of alkali hydroxide for several hours under reflux. A further improvement of the reaction conditions is the use of potassium tcrt-butoxide as base and dimethyl sulfoxide (DMSO) as solvent the reaction can then proceed already at room temperature. ... 

On treatment with a strong base such as sodium hydride or sodium amide, dimethyl sulfoxide yields a proton to form the methylsulfinyl carbanion (dimsyl ion), a strongly basic reagent. Reaction of dimsyl ion with triphenylalkylphosphonium halides provides a convenient route to ylides (see Chapter 11, Section III), and with triphenylmethane the reagent affords a high concentration of triphenylmethyl carbanion. Of immediate interest, however, is the nucleophilic reaction of dimsyl ion with aldehydes, ketones, and particularly esters (//). The reaction of dimsyl ion with nonenolizable ketones and... 

C ( propyl) N phenylmtrone to N phenylmaleimide, 46, 96 semicarbazide hydrochloride to ami noacetone hydiochlonde, 46,1 tetraphenylcyclopentadienone to diphenyl acetylene, 46, 44 Alcohols, synthesis of equatorial, 47, 19 Aldehydes, aromatic, synthesis of, 47, 1 /3-chloro a,0 unsaturated, from ke tones and dimethylformamide-phosphorus oxy chloride, 46, 20 from alky 1 halides, 47, 97 from oxidation of alcohols with dimethyl sulfoxide, dicyclohexyl carbodumide, and pyndimum tnfluoroacetate, 47, 27 Alkylation, of 2 carbomethoxycyclo pentanone with benzyl chloride 45,7... 

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-... 

The reaction of the aldehyde 174, prepared from D-glucose diethyl dithio-acetal by way of compounds 172 and 173, with lithium dimethyl methyl-phosphonate gave the adduct 175. Conversion of 175 into compound 176, followed by oxidation with dimethyl sulfoxide-oxalyl chloride, provided diketone 177. Cyclization of 177 with ethyldiisopropylamine gave the enone 178, which furnished compounds 179 and 180 on sodium borohydride reduction. 0-Desilylation, catalytic hydrogenation, 0-debenzyIation, and acetylation converted 179 into the pentaacetate 93 and 5a-carba-a-L-ido-pyranose pentaacetate (181). 

Alkyltriphenylphosphonium halides are only weakly acidic, and a strong base must be used for deprotonation. Possibilities include organolithium reagents, the anion of dimethyl sulfoxide, and amide ion or substituted amide anions, such as LDA or NaHMDS. The ylides are not normally isolated, so the reaction is carried out either with the carbonyl compound present or with it added immediately after ylide formation. Ylides with nonpolar substituents, e.g., R = H, alkyl, aryl, are quite reactive toward both ketones and aldehydes. Ylides having an a-EWG substituent, such as alkoxycarbonyl or acyl, are less reactive and are called stabilized ylides. 

The aldehyde 38 was obtained from 35, by way of 36 and 37, by the carbodiimide—dimethyl sulfoxide oxidation procedure52 in the presence of 3-(3-dimethylaminopropyl)-l-ethylcarbodiimide hydrochloride (EDAC)53 and dichloroacetic acid. It was isolated in the form of its crystalline 1,3-diphenylimidazolidine derivative (39) by trapping the freshly prepared aldehyde 38 with N,N -diphen-ylethylenediamine. (This reagent was developed by Wanzlick and Lochel54 for the selective derivatization of aldehydes, and has been exploited for the isolation of nucleoside 5 -aldehydes55 and other aldehydo derivatives of carbohydrates by Moffatt and coworkers.52(b))... 

The reducing properties of organic compounds of sulfur, such as methyl mercaptan, show up in partial reduction of trigeminal to geminal dihalides [243]. Dimethyl sulfide reduces hydroperoxides to alcohols and ozonides to aldehydes while being converted to dimethyl sulfoxide [244]. 

The direct oxidative conversion of primary halides or tosylates to aldehydes can be carried out by reaction with dimethyl sulfoxide under alkaline conditions. Formulate a mechanism for this general reaction. 

The present method is practical and efficient as it employs readily available enantioenriched propargylic alcohols as precursors to the allenylindium reagents. With achiral aldehydes the diastereoselectivity is high for branched aldehydes, moderate for unbranched aldehydes, and low for benzaldehyde (Table I). With cHral a-methyl aldehydes the additions proceed under effective reagent control to afford anti adducts of high ee and with excellent diastereoselectivity (eq. 1 and 2). Comparable results were obtained with 3 1 dimethyl sulfoxide-tetrahydrofuran (DMSO-THF) as the solvent. 

To prevent overoxidation of aldehydes, the very mild oxidant dimethyl sulfoxide or dmso, is used to react with T halides or sulfonates to give aldehydes. These reactants are in the same oxidation level as alcohols ... 

Primary alkyl halides (chlorides, bromides, and iodides) can be oxidized to aldehydes easily and in good yields with dimethyl sulfoxide.311 Tosyl esters of primary alcohols can be similarly converted to aldehydes,312 and epoxides313 give a-hydroxy ketones or aldehydes.314 The reaction with tosyl esters is an indirect way of oxidizing primary alcohols to aldehydes (9-3). This type of oxidation can also be carried out without isolation of an intermediate ester The alcohol is treated with dimethyl sulfoxide, dicyclohexylcarbodiimide (DCC),315 and anhydrous phosphoric acid.316 In this way a primary alcohol can be converted to the aldehyde with no carboxylic acid being produced. 

Iodine-Mercury(II) oxide, 149 a-METHYLENE ALDEHYDES AND KETONES 1,4-Diazabicyclo[2.2.2]octane, 92 Dimethyl sulfoxide, 124 Formaldehyde, 136 Methoxyallene, 177 Methylene cycloalkanes By cyclization reactions Diacetatobis(triphenylphos-phine)palladium(II), 91 l-Hydroxy-3-trimethylsilylmethyl-3-butene, 147... 

A different semisynthetic method involves the acylation of an amino alcohol with a peptide ester and the resulting amino alcohol is subsequently oxidized to the aldehyde 40 The acylation of H-Phe[CH2OH] with the peptide ester Z-Ala-Ala-Leu-OMe is carried out in 5% DMF/MeCN with the subtilisin distributed on the surface of macroporous silica gel. The resulting peptide alcohol is oxidized under mild conditions using anhydrous dimethyl sulfoxide and 20-fold excess of acetic anhydride with purification via flash chromatography 40] Z-Phe[CH2OH] has been oxidized under these conditions and the optical rotation indicates little epimerization as compared to literature values 11 40 ... 

During some couplings of nucleosides, promoted by dicyclohexylcarbodii-mide (DCC), Pfitzner and Moffatt.13 decided to try dimethyl sulfoxide (DMSO) as solvent. Instead of obtaining the expected couplings, they observed oxidation of alcohols to aldehydes and ketones. These oxidations were very remarkable, because at that time, on the nucleosides tested, no oxidants were known to be able to deliver efficiently the observed aldehydes and ketones. Furthermore, contrary to many other oxidants, no over-... 

An unsuccessful attempt was next made to simplify the problem of purifying the product by using dioxane as the extracting solvent with only enough benzaldehyde for solvolysis. Finally, on the assumption that an acetal should be as effective in transacetalization as an aldehyde or ketone, the benzaldehyde was replaced by 2,2-dimethoxypropane. In several experiments the hydrogen chloride was replaced by -toluenesulfonic acid also, dimethyl sulfoxide was tried instead of dioxane. All these experiments are summarized in Table I, and they lead to the following conclusions ... 

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