Anhydrides with sulfoxides

Horner, L., Kaiser, P. The course of substitution. XVIII. The reaction of carboxylic acid anhydrides with sulfoxides. Ann. 1959, 626, 19-25. 

In analogy to the properties of ordinary sulfonium salts, reaction of disulfonium dications with bases may lead to either a- or p-deprotonation. Deprotonation of the S-S dication formed during the Pummerer rearrangement of monosulfoxides of certain bis-sulfides 13, 59, 56 is a key step of the overall process. Furukawa and co-workers " also suggested that direct formation of disulfonium dication ylides occurred upon treatment of sulfinyli-mines of 14 and 41 with potassium tert-butoxide. Reaction of triflic anhydride with sulfoxide 100 affords sulfonium salt 102 through deprotonation of the corresponding S-S dication 101 (Scheme 39). ... 

Transformations of Methyl 5-0-Benzyl-2-0-methyl-/3-I)-glueofuranosidurono-6,3-lae-tone (86) to Dimethyl (Z,E)-2-Methoxy-5-(phenylmethoxy)-2,4-hexadienedioatevl (87). ( Elimination employing DBU b oxidation with silver oxide-sodium hydroxide followed by diazomethane esterification c acidic glycoside cleavage, oxidation by dimethyl sulfoxide-acetic anhydride with formation of 5-0-benzyl-2-0-methyI-D-glucaro-1,4 6,3-dilactone, elimination by using DBU, followed by short treatment with diazomethane d elimination by DBU with subsequent diazomethane esterification e sodium borohydride in hexamethylphosphoric triamide 1 catalytic oxidation followed by short treatment with diazomethane " dimethyl sulfoxide-sulfur trioxide-pyridine-triethylamine.150)... 

The S- and Se-(perfluoroalkyl)dibenzothiophenium salts 17-27 were synthesized according to three methods (Eq. 4) (1) fluorination of the corresponding sulfide 1-6 or 8 or selenide 11 or 12 with F2 in the presence of an acid or a Lewis acid (2) fluorination with F2, followed by treatment with an acid or a Lewis acid and (3) treatment of sulfoxide 13, 14, or 15 or selenoxide 16 with triflic anhydride (Tf20). Sulfoxides 13-15 and selenoxide 16 were prepared by oxidation of the corresponding sulfides or selenide with m-chloroperbenzoic acid. 

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 ... 

To determine the diastereoselectivity of the above bora-ene reaction, boronate 193 derived from a-pinene was synthesized. Reaction of a-pinene 192 with Schlosser s base (BunLi + KOBu ) furnishes the allyl carbanion, which upon treatment with triisopropyl borate and subsequent transesterification with pinacol yields a-pinanyl pinacol boronate 193. Bora-ene reaction with this allyl boronate and S02 at — 78 °C in CH2CI2 yields the mixed anhydride 194 as a 2.3 1 mixture of diastereomers upon removal of excess S02. Treatment of this mixture of anhydrides with aryl Grignard led to the formation of two diastereomers of aryl sulfoxides 195 in 3.2 1 ratio (Scheme 33) <2006TL2783>. 

Table 2 also indicates that the nucleophiles effective for vinyl ethers are relatively mild, when compared with those for isobutene (cf., Section V.B.2). In fact, stronger bases lead to inhibition or severe retardation of polymerization [36,64] ketones aldehydes, amides, acid anhydrides, dimethyl sulfoxide (retardation) alcohols, aliphatic amines, pyridine (inhibition). The choice of nucleophiles is determined by their Lewis basicity (as measured by pKb, etc. [64,103]), and this factor determines the effic-tive concentrations of the nucleophiles. For example, the required amounts of esters and ethers decrease in the order of increasing basicity (i.e., a stronger base is more effective and therefore less is needed) [101,103] tetrahydrofuran < 1,4-dioxane ethyl acetate < diethyl ether. On the other hand, for amines not only basicity but also steric factors play an important role [142] thus, unsubstituted pyridine is an inhibitor, while 2,5-dimethylpyridine is an effective nucleophile for controlled/living polymerization, although the latter is more Lewis basic. 

In the synthesis of (S)-zearalenone and of a chiral spiroac-etal, (2S,6/ )-2-methyl-l,7-dioxaspiro[5.6]dodecane, the starting product was a functionalized 3-keto sulfoxide resulting from the reaction of glutaric anhydride with lithiated (+)-(7 )-methyl p-tolyl sulfoxide (eq 6). 

NaHCOs, and methanesulfonic anhydride.Dimethyl sulfoxide in 48% HBr oxidizes benzylic alcohols the aryl aldehydes.Note that Swern oxidation of molecules having alcohol moieties, as well as a disulfide, leads to the ketone without oxidation of the sulfur. Sulfoxides other than DMSO can be used in conjunction with oxalyl chloride for the oxidation of alcohols,including fluorinated sulfoxides and a polymer-bound sulfoxide. ... 

Triflic anhydride in the presence of a base such as DTBMP is the most frequently used promoter with sulfoxides. It has also been used with lanthanide triflates as coactivators [215]. Promoters other than triflic anhydride for the activation of sulfoxides for glycosylation include TfOH [249,250], TMSOTf in the presence of triethylphosphite [251], the heteropolyacid H3PW12O40 [252], the zirconocene reagent Cp2ZrCl2-AgC104 [253] and iodine and iodine monobromide [254,255]. 

Reaction with Sulfoxides and Phosphine Oxides. Sulfoxides and phosphine oxides can be reduced to the corresponding sulfide and phosphine in the presence of triflic anhydride and a mild reducing agent. 

The first commercial polyimide was produced by the polycondensation of pyromellitic anhydride with 4,4 -diaminodiphenyl ether. The first stage is carried out in very polar solvents such as dimethyl formamide, dimethyl acetamide, tetramethyl urea, or dimethyl sulfoxide, when what is known as polyamic acid is formed ... 

Acetic anhydride Ring closures with sulfoxides 3,l-Benzoxathian-4-ones from o-carboxysulfoxides Ac,0 o... 

Low DS starch acetates ate manufactured by treatment of native starch with acetic acid or acetic anhydride, either alone or in pyridine or aqueous alkaline solution. Dimethyl sulfoxide may be used as a cosolvent with acetic anhydride to make low DS starch acetates ketene or vinyl acetate have also been employed. Commercially, acetic anhydride-aqueous alkaU is employed at pH 7—11 and room temperature to give a DS of 0.5. High DS starch acetates ate prepared by the methods previously detailed for low DS acetates, but with longer reaction time. 

The initiating step in these reactions is the attachment of a group to the sulfoxide oxygen to produce an activated intermediate (5). Suitable groups are proton, acyl, alkyl, or almost any of the groups that also initiate the oxidations of alcohols with DMSO (40,48). In a reaction, eg, the one between DMSO and acetic anhydride, the second step is removal of a proton from an a-carbon to give an yUde (6). Release of an acetate ion generates the sulfur-stabilized carbonium ion (7), and the addition of acetate ion to the carbonium ion (7) results in the product (eq. 15) ... 

Cellulose dissolved in suitable solvents, however, can be acetylated in a totally homogeneous manner, and several such methods have been suggested. Treatment in dimethyl sulfoxide (DMSO) with paraformaldehyde gives a soluble methylol derivative that reacts with glacial acetic acid, acetic anhydride, or acetyl chloride to form the acetate (63). The maximum degree of substitution obtained by this method is 2.0 some oxidation also occurs. Similarly, cellulose can be acetylated in solution with dimethylacetamide—paraformaldehyde and dimethylformamide-paraformaldehyde with a potassium acetate catalyst (64) to provide an almost quantitative yield of hydroxymethylceUulose acetate. 

Thermolysis of trithiane (69) or carbonate (70) at reduced pressure yields methylene-thiirane which is stable in cold, dilute solution (Scheme 152) (78JA7436, 78RTC214). A novel acenaphthylene episulfide is obtained by treatment of the six-membered sulfoxide (71) with acetic anhydride (Scheme 153) (68JA1676), and photolysis of (72) gives a low yield of episulfide (73 Scheme 154) (72JA521). Low yields may be due to the desulfurization of the thiiranes under the reaction conditions. 

Vicinal glycols may be oxidized to the corresponding 17a-hydroxy-20-ketones in reasonable yields by means of chromium trioxide in dimethylfor-mamide in the presence of manganese dichloride, or by treatment with dimethyl sulfoxide-acetic anhydride. ... 

Dimethyl sulfoxide reacts with trifluoroacetic anhydride at low tempera ture to give a complex that is an efficient reagent for the oxidation of alcohols to carbonyl compounds [40 41] This reagent can be used to oxidize primary and secondary aliphatic alcohols, cycloalkyl alcohols, and allylic, homoallylic, ben-zylic, acetylenic, and steroidal alcohols (equation 19)... 

Fortunately, the oxidation of l,2 5,6-di-0-isopropylidene-a-D-glucofura-nose to l,2 5,6-di-0-isopropylidene-a-D-nfoo-hexofuranos-3-ulose (1) can be accomplished using either phosphorus pentoxide (10, 44) or acetic anhydride (10, 52) in methyl sulfoxide although this oxidation is effected with ruthenium tetroxide (6,7, 46), it is exceeding difficult with other oxidizing agents (53). Keto-sugar 1 is reduced stereospecifically... 

The crystalline phenylboronate derived by similar treatment of methyl a-L-fucopyranoside was shown to possess the 3,4-cyclic structure (25). This assignment is based on oxidation of compound 25 with methyl sulfoxide-acetic anhydride and the chromatographic identification of... 

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