Sulfide, substituted

Perfluoroalkylcopper reagents react with thiocyanates to give perfluoro-alkyl-substituted sulfides in low yields [230] and with benzoylformyl chloride to give the oi-diketone in 49% yield [231] However, other a-ketoacyl halides were prepared in less than 5% yield [231]... 

Sila-Pummerer reaction of the /1-ketosulfoxide 1257 with the enol silyl ether of acetophenone 653 in the presence of BSA 22 a and stannous triflate affords the C-substituted sulfide 1258 in 82% yield and HMDSO 7 [52]. The allylic sulfoxide 1259 reacts with 653 in the presence of TMSOTf 20/DIPEA to give the unsaturated sulfide 1260 in 62% yield or, with the enol silyl ether of cyclohexanone 107a , the unsaturated sulfide 1261 in 63% yield and HMDSO 7 [53] (Scheme 8.21). 

The reactions of H and F with CH3S are exothermic by 259 and 393 kJ mol-1, respectively, and either could be responsible for formation of CH2S(A3S) [7], Methylated sulfur compounds produce intense emission from HCF, while the corresponding ethyl-substituted compounds produce only trace or no HCF [6]. Emission from HFf was much stronger for the ethyl-substituted than for the methyl-substituted sulfides [6], This suggests that methyl radicals, formed perhaps in Reaction (34), lead to the formation of HCF. Emission of HCF has been identified in F2/CH4 flames [70] where it is attributed to the association reaction... 

The preparative electrochemical oxidation of silyl-substituted sulfides results in the cleavage of the C Si bond [36-38]. For example, the anodic oxidation of 1-phenylthio-l-trimethylsilylalkanes takes place smoothly in methanol in an undivided cell equipped with a carbon rod anode and a carbon rod cathode. Although 1-methoxy-l-phenylthioalkanes are formed as the initial products, they are converted into 1,1-dimethoxyalkanes during the course of the reaction (Scheme 8). The electrochemical reaction in the presence of diols such as ethylene glycol affords the corresponding cyclic acetals. 

T(—H) can also be formed in a two-step process involving radical cation formation produced by photosensitizers operating through a type I mechanism, followed by deprotonation. Cadet has also developed the photolabile phenyl sulfide precursor that upon irradiation at 254nm generates T(—H). " The corresponding phenyl selenide" and methoxy-substituted sulfides" were developed by the Greenberg... 

A recent report describes replacing the dimethyl sulfide with larger alkyl-substituted sulfides to... 

R = substituted sulfide, tertiary amine, quaternary ammonium,... 

AIkylthio)allylritanium reagentS, RSCH=CHCH2TiL (l).9 The reagents are prepared by deprotonation of allylic alkyl (aryl) sulfides with sec- or r-butyllithium followed by addition of Ti(0-/-Pr)4 at - 78°. They can react with carbonyl compounds at the a- or "/-position. a-Adducts predominate in reactions with a- and /1-mono- and disubstituted sulfides, whereas /-adducts predominate in reaction with /-substituted sulfides. The a-adducts show high eryr/iro-selectivity. The products are useful precursors to alkenyl oxiranes and to 2-(arylthio)-l,3-butadienes. 

This catalytic system proved to be highly efficient. Thus, a low catalytic amount of Fe(acac)3 (5-10 mol%) permits the successful imination of a broad variety of substituted sulfides and sulfoxides. The best results were obtained with nosyl sulfonamide as nitrogen source (Figure 3.11). Moreover, as previously observed with FeCl2, this catalyst also iminates sulfides more readily than sulfoxides. 

The sulfide fraction of non-biodegraded petroleums usually contains a complement of n-alkyl substituted sulfides, thiolanes and thianes, in addition to the terpenoid class. In the biodegraded Alberta oil sand bitumens, however, n-alkyl substituted sulfides are absent. The two classes of sulfides can be separated by thiourea adduction, the n-alkyl-containing molecules being adducted. Raney nickel reduction of the Bellshill Lake sulfides (1 11 yielded a series of n-alkanes showing a distribution quite similar to that of the n-alkanes in the saturate fraction of this oil. In some oils the thiolane and thiane concentrations are commensurate, e.g. Houmann, Figure 13 in others, the concentration of thianes may be small compared to thiolanes. 

The Pummerer rearrangement of sulfoxides with acid anhydrides has been extensively utilized as a method for the synthesis of a-substituted sulfides. When a,(3-unsaturated sulfoxides are used, the initial formed oxysulfonium ion may undergo two different pathways the additive Pummerer reaction or the vinylogous Pummerer reaction. The following sections will consider examples from both pathways. 

The phenyl-substituted sulfide 91 (R = Ph) was used for the synthesis of various a-disubstituted phosphepines 93 via sequential deprotonation steps with Bu Li and subsequent treatment with trimethylsilyl chloride (TMS-C1), alkyl iodide, or benzyl bromide <2005TA3416>. 

Trifluoromethyl-substituted sulfides, sulfoxides, and sulfones can undergo [4-F 2]-cycloaddition reactions with various dienes under thermal conditions (Table 2) sec also formation of 15 and 17. 5... 

All sulfides exhibit a first voltammetric oxidation peak corresponding to an overall electricity consumption of one electron. For most of the p ra-substituted compounds (XVII), a first reversible step was observed, whereas for compounds XVI this step showed to be irreversible. Preparative electrolyses of all p-substituted sulfides (XVII) yield sulfo-nium salts under controlled-potential conditions, and all, except the p-MeO-substituted one, revealed the same regioselectivity for the S-C bond formation. 

Good electron donors such as sulfides, phosphines, or arsines can react with N-fluoropyridinium cation by a single-electron transfer (SET) pathway. This conclusion was reached after finding products known to be derived from free-radical processes. For example, it is believed that the SET process is operative in the reaction of sulfides (74) to give pyridyl-substituted sulfides (78) through the intermediary of a radical 75 and a radical cation 76 (Scheme 7). In addition to 78 this reaction produces a dimer of a radical 77 derived from the radical cation (76) and a number of other products known to be formed from 76 or 77 (93JHC329). The... 

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