Acylation of sulfones

If the reagent is too precious to waste, another device is to use two molecules of base for every one of the compound. In this way there is always a molecule of strong base waiting to remove a pro-, ton from the product. The acylation of sulfones with esters is a good example. 

Fluorosulfuric acid [7789-21-17, HSO F, is a colodess-to-light yellow liquid that fumes strongly in moist air and has a sharp odor. It may be regarded as a mixed anhydride of sulfuric and hydrofluoric acids. Fluorosulfuric acid was first identified and characterized in 1892 (1). It is a strong acid and is employed as a catalyst and chemical reagent in a number of chemical processes, such as alkylation (qv), acylation, polymerization, sulfonation, isomerization, and production of organic fluorosulfates (see Friedel-CRAFTSreactions). 

Sulfonated styrene—divinylbensene cross-linked polymers have been appHed in many of the previously mentioned reactions and also in the acylation of thiophene with acetic anhydride and acetyl chloride (209). Resins of this type (Dowex 50, Amherljte IR-112, and Permutit Q) are particularly effective catalysts in the alkylation of phenols with olefins (such as propylene, isobutylene, diisobutylene), alkyl haUdes, and alcohols (210) (see Ion exchange). Superacids. 

Important analogs of aniline include the toluidines, xyUdines, anisidines, phenetidines, and its chloro-, nitro-. A/-acetyl. A/-alkyl. A/-aryl. A/-acyl, and sulfonic acid derivatives. 

Orthoesters. The value of cycHc orthoesters as intermediates for selective acylation of carbohydrates has been demonstrated (73). Treatment of sucrose with trimethylorthoacetate and DMF in the presence of toluene-/)-sulfonic acid followed by acid hydrolysis gave the 6-0-acetylsucrose as the major and the 4-0-acetylsucrose [63648-80-6] as the minor component. The latter compound underwent acetyl migration from C-4 to C-6 when treated with an organic base, such as / fZ-butylamine, in DMF to give sucrose 6-acetate in >90% yield (74). When the kinetic reagent 2,2-dimethoxyethene was used,... 

Cefsulodin (60) has a sulfonic acid nx)iety on the C-7 acyl side chain. This moiety conveys antipseudomonal activity to certain penicillins, and it is interesting to note that this artifice works with cefsulodin as well. It is also interesting that, in contrast to the other so-called third-generation cephalosporins, the spectrum of cefsulodin is rather narrow and its clinical success will place a premium upon accurate diagnosis. Its synthesis begins by acylation of... 

TABLE 2. Sulfones from S-acylations of sulfmate anions RSOz... 

Among other methods for the preparation of alkylated ketones are (1) the Stork enamine reaction (12-18), (2) the acetoacetic ester synthesis (10-104), (3) alkylation of p-keto sulfones or sulfoxides (10-104), (4) acylation of CH3SOCH2 followed by reductive cleavage (10-119), (5) treatment of a-halo ketones with lithium dialkyl-copper reagents (10-94), and (6) treatment of a-halo ketones with trialkylboranes (10-109). 

The method is not restricted to secondary aryl alcohols and very good results were also obtained for secondary diols [39], a- and S-hydroxyalkylphosphonates [40], 2-hydroxyalkyl sulfones [41], allylic alcohols [42], S-halo alcohols [43], aromatic chlorohydrins [44], functionalized y-hydroxy amides [45], 1,2-diarylethanols [46], and primary amines [47]. Recently, the synthetic potential of this method was expanded by application of an air-stable and recyclable racemization catalyst that is applicable to alcohol DKR at room temperature [48]. The catalyst type is not limited to organometallic ruthenium compounds. Recent report indicates that the in situ racemization of amines with thiyl radicals can also be combined with enzymatic acylation of amines [49]. It is clear that, in the future, other types of catalytic racemization processes will be used together with enzymatic processes. 

Silica sol-gel inunobihzed La(OTf)3 (Scheme 48.2B) previously used in the acylation of a series of alcohols and activated aromatic compounds using acetic anhydride as acylating agent, showed a poor activity compared with other various sihca sol-gel inunobihzed triflate derivatives (tert-butyl-dimethylsilyl-trifluoromethane-sulfonate (BDMST), or trifhc acid (HOTf)). Acylation at the aromatic ring occurred over the BDMST and HOTf catalysts, while the La(OTl)3 catalysts only led to O-acetylated products [22]. Such behavior is characteristic... 

These reactions accomplish the same overall synthetic transformation as the acylation of ester enolates, but use desulfurization rather than decarboxylation to remove the anion-stabilizing group. Dimethyl sulfone can be subjected to similar reaction sequences.232... 

Ester formation from polysaccharides can be achieved in several ways First by acylation of the OH groups with carboxylic or sulfonic acid azolides, second by converting the OH groups with imidazole carboxylates into carbonates, and third by reaction of an acid leash on the polysaccharide with an alcohol by means of CDI or analogous azolides. The acid leash might, for example, be a succinate attached to the polysaccharide. 

The importance of reactions with complex, metal hydrides in carbohydrate chemistry is well documented by a vast number of publications that deal mainly with reduction of carbonyl groups, N- and O-acyl functions, lactones, azides, and epoxides, as well as with reactions of sulfonic esters. With rare exceptions, lithium aluminum hydride and lithium, sodium, or potassium borohydride are the... 

The syntheses of 1 utilized the Ullmann ether synthesis.13 Reaction of 2 mol of 1-bromonaphthalene with 4,4-(hexafluoroisopropylidiene)diphenol afforded the desired product 1. The reaction was carried out in DM Ac at 160°C in the presence of potassium carbonate as the base and copper (I) iodine as the reaction catalyst to yield 1, as depicted in Scheme 1. The reaction proceeded slowly but in good yield with easy isolation of the desired compound. Acylation of 1 with 4-fluorobenzoyl chloride to prepare 2 was carried out under modified Friedel-Crafts reaction conditions14 using dimethyl-sulfone as catalyst moderator. Both 1 and 2 were easily recrystallized to yield high-purity monomers suitable for polymerizations. 

Aromatic compounds, 13 108-109 13 680. See also Aromatics acylation of, 12 173-181 amination of, 12 184 arylation of, 12 170-171 Cycloalkylation of, 12 169 in diesel fuel, 12 425 formylation of, 12 178 Friedel-Crafts acylation of, 12 174 Friedel-Crafts alkylation of, 12 164 nitration of, 12 182-183 oxidative coupling of, 19 654 sulfonation of, 12 181 sulfonation reagents for, 23 521-524 Aromatic-containing polymers, sulfonation of, 23 535-536... 

The third procedure illustrated by this preparation involves the reaotion of ketones with trifluoromethanesulfonic anhydride in a solvent such as pentane, methylene chloride, or carbon tetrachloride and in the presence of a base such as pyridine, lutidine, or anhydrous sodium carbonate.7-11,15 This procedure, which presumably involves either acid-catalyzed or base-catalyzed enolization of the ketone followed by acylation of the enol with the acid anhydride, has also been used to prepare other vinyl sulfonate esters such as tosylates12 or methanesulfonates.13... 

The 1,3,2-dioxastannolanes are important in organic synthesis because they can readily be derived from dialkyltin oxide and 1,2-diols, as in carbohydrates the reaction can be carried out in toluene in a few minutes under microwave irradiation.387 The dioxastannolanes can then be subjected to regioselective reaction with an electrophile such as an acyl chloride (Equation (140)) or sulfonyl chloride, or an isocyanate. The acylation or sulfonation can be carried out with catalytic amounts of the dialkyltin oxide, including the recoverable (C6F13CH2CH2)2Sn0.388... 

Primary alkyl phenols have been prepared by the reduction of acyl phenols 1 by the demethylation of the corresponding ethers 12 by the diazotization of the corresponding amines 3 and by the alkali fusion of sulfonates.4 Alkyl resorcinols have been prepared by the reduction of acyl resorcinols.1 5 6 Alkyl chlororesorcinols have been prepared from the corresponding acyl chlororesorcinols by reduction.7... 

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