Alkyl sulfites, preparation

Alkyl phosphates, preparation, 16, 9 Alkyl sulfates, preparation, 19, 27 Alkyl sulfides, preparation, 15, 72 Alkyl sulfites, preparation, 19, 29 Ai-AlkyW -toluidines, 18,42 Allanioin, 13,1 Allyl alcohol, 10, 107 16, 85 Allylamine, 18, 5 Allyl cyanide, 16, 85 Allyl isothiocyanate, 18, 5 Alumina, 17, 27... 

Heating the adduct of ethylene oxide and sulfur dioxide with primary alcohols in the presence of alkaH hydhdes or a transition-metal haHde yields dialkyl sulfites (107). Another method for the preparation of methyl alkyl sulfites consists of the reaction of diazomethane with alcohoHc solutions of sulfur dioxide (108). 

Secondary alkyl sulfites are produced if the formed hydrogen chloride is removed by carrying out the reaction at reduced pressure (aspirator) [9], Examples of the preparation of cyclic sulfites from 1,2-diols are shown in Table II. Other examples involving the preparation of cyclic sulfites are found in a recent patent [20],... 

Aromatic polysulfites can be produced if bisphenols, eg, bisphenol A, are heated with diphenyl sulfite in the presence of lithium hydride (112). Halosulfates and Halosulfites. A general method for the preparation of alkyl halosulfates and halosulfites is the treatment of the alcohol with sulfuryl or thionyl chloride at low temperatures while passing an inert gas through the mixture to remove hydrogen chloride (113). 

Between sulfur dioxide radical anions, dithionite, and sulfoxylate/sulfite there exists a pH-dependent equilibrium465 (equation 86). Therefore, dithionite has been used as a source of sulfoxylate in order to prepare sulfinate and hence sulfones. Alkylation with triethyl oxonium fluoroborate leads to ethyl ethanesulfinate, alkyl iodides lead to symmetrical sulfones466 (equation 87). 

Sulfinic acids can be prepared by reduction of sulfonyl chlorides. Though mostly done on aromatic sulfonyl chlorides, the reaction has also been applied to alkyl compounds. Besides zinc, sodium sulfite, hydrazine, sodium sulfide, and other reducing agents have been used. For reduction of sulfonyl chlorides to thiols, see 19-57. 

Unsymmetrical dialkyl peroxides can be prepared by several methods. Some of them are summarized in Scheme 31. Primary " , secondary or tertiary"" " alkyl hydroperoxides can serve as substrates and are converted to the dialkyl peroxides by acid- or base-catalyzed nucleophilic substitution with alkylating agents like dialkyl sulfate " , diazomethane " , dialkyl sulfites, alcohols " or alkyl halides (e.g. in the presence of silver trifluoroacetate) "". An overview of the results obtained utilizing the method mentioned above is given in Table 7. 

Salts of sulfonic acids can be prepared by treatment of primary or secondary alkyl halides with sulfite ion,799 Even tertiary halides have been used, though the yields are low. Epoxides treated with bisulfite give 3-hydroxy sulfonic acids. ... 

Chiral sulfinates, (CH3)3CS(0)0R. Alkyl f-butylsulfinates can be prepared by reaction of /-butylmagnesium chloride with dialkyl sulfites. If the reaction is carried out in the presence of an optically active amine, the products can be optically active. The highest enantioselectivity is observed with amino alcohols, in particular with (-)-quinine (1). 

Alkyl-substituted 1,3,2-dioxathiolane 2,2-dioxides can be prepared in a similar manner to the parent compound, ethylene sulfate (18) (66HC(2l-l)i) (cf. Scheme 10, Section 4.33.4.2.1). The method of choice is the permanganate oxidation of the corresponding cyclic sulfites (cf. Section 4.33.3.2.3) since the direct reaction of 1,2-diols with sulfuryl chloride often proceeds less smoothly than does the reaction with thionyl chloride. 4,5-Diaryl-l,3,2-dioxathiole 2,2-dioxides of type (186) are obtained by treatment of 9,10-... 

Preparation of Chiral Sulfinates. Optically active sulfinates can be prepared by reaction of a symmetrical sulfite with t-Butylmagnesium Chloride in the presence of an optically active amino alcohol. The best enantioselectivity has been observed using quinine as the optically active amine (eq 2)3 An alternative approach to this new enantioselective asymmetric synthesis of alkyl t-butylsulfinates would be reaction of a racemic sulfinate with r-butylmagnesium chloride complexed by optically active alkaloids (eq 3). In this case, kinetic resolution of the racemic sulfinate leads to an optically active sulfinate and an optically active sulfoxide. 

Introduction. It will be recalled that one of the most common methods of distinguishing between aromatic and aliphatic hydrocarbons is the difference in the rates of their reactions with sulfuric acid. Aromatic hydrocarbons readily form sulfonic acids when heated with concentrated sulfuric acid at temperatures varying from 80 to 200 . Saturated paraffin hydrocarbons, on the other hand, do not react with sulfuric acid under comparable conditions. A number of saturated paraffins are sulfonated directly by using fuming sulfuric acid and heating under pressure, but the sulfonic acids of the lower paraffin hydrocarbons are prepared by reacting alkyl halides with alkali sulfites. The sulfonic acids of the aromatic hydrocarbons are of much greater importance than the sulfonic acids of paraffins. 

Both these reagents will react with alkyl halides in aqueous media to give the corresponding sulfonic acids (21). This procedure has been used extensively for the preparation of aliphatic sulfonic acids in good yields (see Chapter 7, p. 100). Sodium hydrogen sulfite will also form sulfonic acids by addition to alkenes in the presence of peroxide catalysts (anti-Markownikoff reaction) (Scheme 19). 

The majority of aliphatic compounds tend to be resistant to direct sulfonation and under forcing conditions often form a complex mixture of products. Consequently, aliphatic sulfonic acids are generally prepared by other methods, such as treatment of an alkyl halide with sodium sulfite (see p. 101). However, in certain cases direct sulfonation works well, namely with terminal alkynes (36) and tertiary alkanes (37) (Scheme 19). 

Preparation. An aqueous solution of hypobromous acid prepared from siiver sulfite and bromine water is shaken with r-butanoi, and the product is extracted with trichlorofluoromethane (Freon 11) and distilled yield 42%. It is a reddish orange liquid with a bromine-like odor and is stable at 0° in the dark for long periods. It is rapidly destroyed at 85° or on irradiation, or by sodium bicarbonate. The reagent reacts with an alkane and bromotrichloromethane to form an alkyl bromide. 

Replacement of the halogen of alkyl halides by treatment with alkali sulfites was first used by Strecker340 in his preparation of aliphatic sulfonic acids ... 

Table 2.13 Preparation of dialkyl and alkyl aryl sulfoxides from cyclic sulfite (34) or (35)...

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