Sulfones reaction with bases

The 1 -phenyl-1 J/-tetrazol-5-yl sulfones do not have a tendency to self-condense, so they can first be deprotonated with base and then reacted with the aldehyde. This makes possible a far milder reaction process, including reactions with base-sensitive aldehydes. 

The sulfonyl halides (ArSOjCl) convert the alcohol into a sulfonate (ArSOjOR), which is a better leaving group than the hydroxyl group. This allows a range of nucleophilic substitutions to be carried out, many of which parallel those found with alkyl halides. Alkyl halides such as iodides are formed by the nucleophilic substitution of the sulfonate by an iodide ion. The reaction in this case proceeds with inversion of configuration. Treatment of the sulfonate esters with bases such as sodium methoxide or collidine (2,4,6-trimethylpyridine), or even just heating them, can lead to the elimination of toluene-4-sulfonic acid and the formation of an alkene. 

Hydrodeanunation. - Primary amino groups can be replaced with hydrogen by treatment with excess hydroxylamine-O-sulfonic acid in an alkaline medium at 0°. The reaction is believed to involve N-amination to a hydrazine (1, 482) followed by reaction with nitrone (HN ), formed by reaction of hydroxylamine-O-sulfonic acid with base. Evidence for this mechanism is the conversion of benzyl-hydrazine to toluene (73% ineld) under the same conditions. 

The products, sulfonic acids, are strong organic acids. Also, they can be converted to phenols by reaction with base at high temperatures. 

Solovyev et al. [60] have shown that the IPr-borane complex can be substituted in a number of different feshions. For instance, reduction of alkyl halides or alkyl sulfonates yields the corresponding NHC-stabilized boryl-halide or sulfonate. Reaction with halogen-based electrophiles also yields boryl-halides. Reactions with Lewis or Bronsted acids (e.g., triflic acid) have also proven successful. These various reactions are especially useful since they result in the addition of a good leaving group, which paves the way for subsequent nucleophilic... 

Section 15 13 Thiols are compounds of the type RSH They are more acidic than alco hols and are readily deprotonated by reaction with aqueous base Thiols can be oxidized to sulfemc acids (RSOH) sulfimc acids (RSO2H) and sulfonic acids (RSO3H) The redox relationship between thiols and disul tides IS important m certain biochemical processes... 

Direct, acid catalyzed esterification of acryhc acid is the main route for the manufacture of higher alkyl esters. The most important higher alkyl acrylate is 2-ethyIhexyi acrylate prepared from the available 0x0 alcohol 2-ethyl-1-hexanol (see Alcohols, higher aliphatic). The most common catalysts are sulfuric or toluenesulfonic acid and sulfonic acid functional cation-exchange resins. Solvents are used as entraining agents for the removal of water of reaction. The product is washed with base to remove unreacted acryhc acid and catalyst and then purified by distillation. The esters are obtained in 80—90% yield and in exceUent purity. 

Convenient syntheses of vinyl fluorides are of synthetic interest, fhe conjugate base of fluoromethyl phenyl sulfone reacts with carbonyl compounds to provide P-tluoro alcohols, which are used to prepare terminal vinyl fluorides [25] (equation 23) (Table 9) This reaction offers an alternative to the Winig reaction, which may be very sensitive to reaction conditions. 

The a -halosulfone, required for the Ramberg-Backlund reaction, can for example be prepared from a sulfide by reaction with thionyl chloride (or with N-chlorosuccinimide) to give an a-chlorosulfide, followed by oxidation to the sulfone—e.g. using m-chloroperbenzoic acid. As base for the Ramberg-Backlund reaction have been used alkoxides—e.g. potassium t-butoxide in an etheral solvent, as well as aqueous alkali hydroxide. In the latter case the use of a phase-transfer catalyst may be of advantage. ... 

In the condensation reaction between chloro- and bromo-methyl aryl sulfones and carbonyl compounds, a-sulfonyloxiranes were obtained. In this condensation reaction, bases such as potassium t-butoxides372, NaH373 and aqueous concentrated hydroxide with benzyltriethylammonium chloride under two-phase condensation were used374. In the reaction with aldehydes only the trans-epoxide isomers resulted, whereas lith-iofluoromethyl phenyl sulfone 289375 and 291376 were found to add to aldehydes affording /J-hydroxysulfones 290 and 292, respectively. 

Block and Aslam441 reported a novel variant of the Ramberg-Backlund reaction in which a,/J-unsaturated a -bromoalkyl sulfones 368 afforded 1,3-dienes upon treatment with base. Since a -bromoalkyl sulfones 368 can be obtained readily by the initial treatment of olefins with bromomethanesulfonyl bromide under photoirradiation and subsequent treatment with triethylamine, this reaction was utilized for preparation of dienes which contain one additional carbon over that of the corresponding olefin. Starting from the cyclic olefins 369-372 the 1,3-dienes 373-376 were obtained442. 

Addition of amines to a,/J-unsaturated sulfones has been used in synthesis of key intermediates of biotin. In this reaction, benzylamine serves first as a base in the reaction with 60 to afford thiophene 1,1-dioxide (61) and also as a nucleophile to introduce two amino groups (equation 57)49. 

Vinyl sulfones such as 262 are smoothly converted to a,) -unsaturated nitriles such as 263 on treatment with KCN in the presence of dicyclohexyl-18-crown-6 in refluxing t-butyl alcohol (equation 155)148. The reaction conditions are compatible with base-labile functionalities such as a methoxycarbonyl group (equation 156)148. This method can be used in the preparation of the sesquiterpene aldehyde nuciferal from allyl phenyl sulfones. 

Based on petrochemicals, linear alkyl benzene sulfonates (LAS) are the most important surfactants. First description can be found in patents from the mid-1930s [2] using Fischer-Tropsch synthesis and Friedel-Crafts reactions. With the beginning of the 1950s the importance of the class of surfactants rose. The main use is in household and cleaning products. 

Bis-o-quinodimethanes have also been used to functionalize [60]-fullerene by Diels Alder reaction. An example is the preparation of main-chain polymers with incorporated [60]-fullerene units [48] illustrated in Scheme 2.20. Cycloaddition of bis-diene 50 generated in situ from bis-sulfone 49 with [60]-fullerene leads to an oligomer mixture 51. Another type of functionalization is based on the... 

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