Fluorosulfonic esters

The solvolytic behavior of arylvinyl sulfonate esters also has been investigated. Jones and Maness were the first to prepare fluorosulfonate esters, 153, from the corresponding triazenes (140). In the solvolytic reactivity... 

Only a few examples of vinyl substitution with aryl fluorosulfonate esters have been reported but the reaction will surely turn out to be general.111 A tetrafluoroethoxytetrafluoroethanesulfonate ester was used in the example shown in equation (50)... 

THE can be polymerized by many strongly acidic catalysts, but not all of them produce the requked bitimctional polyether glycol with a minimum of by-products. Several large-scale commercial polymerization processes are based on fluorosulfonic acid, HESO, catalysis, which meets all these requkements. The catalyst is added to THE at low temperatures and an exothermic polymerization occurs readily. The polymerization products are poly(tetramethylene ether) chains with sulfate ester groups (8). 

Most frequent are oxidations of alkenes that can be converted to a series of compounds such as epoxides, halohydnns and their esters, ozonides (1,2,4 tri-oxolanes), a-hydroxyketones, a-hydroxyketone fluorosulfonates, ot-diketones, and carboxylic acids and their denvatives... 

Octafluoroisobtttylene, whose double bond has reduced electron density and limited accessibility, reacts with sulfur tnoxidg under vigorous conditions The reaction mixture contains various components including bis-oi-tnfluorometh-yldifluoroethane-P-sultone, bis(a-trifluoromethyldifluoroethane)-(i-pyrosultone, the heptafluoroisobutenyl ester of fluorosulfonic acid, and the heptafluoroiso-butenyl ester of fluoropyrosulfomc acid [73] (equation 4)... 

A synthetic acridinium ester, 4-(2-succinimidyloxycarbonylethyl)phenyl-10-methylacridinium-9-carboxylate fluorosulfonate (acridinium NHS) can be used to label unhindered primary amine functionalities (Fig. 6), and using this interface for CL detection, it was later satisfactorily applied for performing trace peptide CE separation with CL detection [81]. In this case, the acridinium labeling of the peptides is done in a precolumn mode, prior to injection. The tagging reaction is run at pH 8, and is determined to reach completion in 15 min by... 

Reaction Scheme I. Polymerization of THE with esters of fluorosulfonic acids... 

Fluorosulfonate ion, 2 124-125 Fluorosulfonic acid, 2 123-124, 145, see also Fluorosulfuric acid esters, 2 126-127, 145 Fluorosulfonylamide ions, 19 193-206 Fluorosulfonyl-nitrogen compounds, syntheses and properties of, 14 363-372 iV-Fluorosulfonylpentafluorosulfanylamine, 19 190, 191... 

Other pseudo-halides are used for carbonylation. Phenyl fluorosulfonate (484) can be carbonylated to give benzoate[337]. Aryl(aryl)iodonium salts[338], aryl(alkenyl)iodonium salts (485)[339], and aryl(alkynyl)iodonium salts (486)[340] are reactive compounds and undergo carbonylation under mild conditions (room temperature, 1 atm) to give aryl, alkenyl, and alkynyl esters. Iodoxybenzene (487) is carbonylated under mild conditions in... 

If LiMe is used as the base, addition to the ester function, followed by elimination of acetone, affords the dianion (8), which gives the dimethylvi-nylidene complex (9) on treatment with methyl fluorosulfonate (27) ... 

An example of an er-fluorosulfonic acid ester is provided in the same scheme. Lastly, there is a comparison of a bis-sulfone and the carbanion formed by deprotonation. Note the significant shielding of the fluorine substituent in the carbanion. 

Sulfuric-fluorosulfonic acid mixtures give complete cyclization of allyl and methallyl esters and thiol esters to give the l,3-dioxolan-2-ylium and l,3-oxathiolan-2-ylium cations (72CRV357) as shown in equation (29). Such cations are frequently involved in the solvolysis of haloacyl derivatives. This neighboring group effect has important mechanistic and stereochemical consequences, and is frequently encountered when working with carbohydrates. 

The quaternization of 1-substituted imidazoles is usually easy unless steric factors intervene, or strongly electron-attracting groups are present, for example, 1-acylimidazoles can only be alkylated at N(3) with powerful alkylating agents such as methyl fluorosulfonate or trialkyloxonium fluoroborates. Trimethyloxonium fluoroborate does not methylate 1-dimethylaminosulfonylimidazole. Regiospecific synthesis of 3-substituted L-histidines can be achieved by alkylation of Ar-/-butoxycarbonyl-l-phenacyl-L-histidinc methyl ester at N(3), followed by reductive removal of the phenacyl group (Scheme 15). 

TOSMIC can be converted into an A-tosylmethylimidic ester or thioester (10) which will react with an aldimine to form a 1,2,5-trisubstituted imidazole (Scheme 4.2.3). These esters (10) can be made from A-tosylmethylacetamidc (from the Mannich condensation of p-toluenesulfonic acid, formaldehyde and acetamide [10]), which is smoothly converted by P4S10 in DME into the thioamide which forms the 5-methylated imidate when treated with methyl fluorosulfonate in dichloromethane. Yields of the Al-tosylmethylimidic thioesters are good (65-93%) they are fairly stable crystalline solids which are best stored under nitrogen at —20°C. In reaction with an aldimine in the presence of sodium hydride or potassium t-butoxide (in DME -DMSO or... 

The action of oxonium salts on vinylogous amides affords iminium salts (71 equation 44), which are useful for synthetic purposes in heterocyclic chemistry. ° " - Alkyldiphenylsulfonium tetrafluoro-borates (72 equation 45) were recommended as reagents which alkylate amides and lactams under smooth conditions.2 2 With the aid of fluorosulfonic acid esters as well as with trifluorometh-anesulfonic acid esters, - - which have alkylation power comparable to oxonium salts, iminium salts, e.g. (73) and (74 Scheme 5), could be synthesized from amides, - vinylogous amides and lactams. Trimethylsilyloxymethyleneiminium salts (75 equation 46) are accessible by reacting tri-methylsilyltrifluoromethanesulfonate with amides. - ... 

The action of a Zn/Cu couple on 1,3-dibromo ketones and secondary amides yields 2-dialkylamino-1,3-dioxolanes (451 equation 208). Fluorosulfonic peracid anhydride adds to trifluoroacetonitrile to give an amide acetal (452 equation 209). In the addition of (Z)-2-butene-l,4-diol to trichloroacetoni-trile, catalyzed by sodium, the 1,3-dioxepin (453 equation 210) is produced. Bicyclic amide acetals (454 equation 211) are byproducts in the reaction of lactim ethers with diketene. TTie methyl esters of perfluorinated carboxylic acids react with diethanolamine to afford bicyclic amide acetals (455 equation 212). Heating of maleic anilides (456 equation 213) with acetic acid anhydride/sodium acetate gives heterocyclic compounds (457) containing an amide acetal structure. ... 

Cyclodehydration Aluminum chloride see also Methyl fluorene-9-carboxylate). Dowtherm. Fluorosulfonic acid. Hydrogen fluoride. Perchloric add. Phosphorus pentoxide. Phosphoryl chloride. Polyphosphate ester. Polyphosphoric add. Potassium bisulfate. Sodium aluminum chloride. Sulfur trioxide-Dimelhylformamide. />-Toluenesulfonic acid. Trifluoroacetic acid. Trifluoroacetic anhydride. 

ALKYLATION Benzyltriethylammonium chloride. 9-Borabicyclo [ 3.3.1 ] nonane. Dimethylcopperlithium. 1,3-Dithiane. Hexamethyl-phosphoric triamide. Lithiumdi-isopropylamide. Lithium diisopropylamide Methyl fluorosulfonate. Naphthalene -Lithium. Phenacylsulfonyl chloride. Polyphosphate ester Silver oxide. Triethylaluminum. Triethyl-oxonium fluoroborate. 

Nucleophiles with two sites that could react with electrophiles are called ambident nucleophiles. The Hard and Soft Acids and Bases (HSAB) principle applies because a hard electrophile reacts at the harder nucleophilic site and a soft electrophile at the softer nucleophilic site. For instance, the sulfenate ion 70 is an ambident nucleophile, because it reacts (a) with methyl fluorosulfonate, a hard electrophile, at the oxygen atom, where most of the negative charge is concentrated, to give the sulfenate ester 71 and (b) with methyl iodide, a soft electrophile, to give the sulfoxide 72. Sulfur atom is the softer of the two nucleophilic sites available in the sulfenate ion and, furthermore, it is rendered more nucleophilic by the a-effect arising from the adjacent oxygen atom. 

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