Alkyl aryl thioethers

ALKYL-l-ALKYNES, 58, 1 ALKYL ARYL SULFIDES, 58,143 Alkyl aryl thioethers, 58,145 Alkylation, enolates, 56, 52 C-ALKYLATION, phase transfer catalysis... 

Alkyl aryl thioethers from thioiminium salts... 

Powdered KOH (0.17 g, 3 mmol) is added to the freshly prepared thioiminium halide [MeC(SR)NH2+Cl- or McC(SR)NMc2+C1 ] (3 mmol) and TEBA-C1 (0.12 g, 0.5 mmol) in CH2C12 (30 ml). The mixture is stirred at room temperature until the reaction is complete, as shown by TLC analysis. The organic phase is separated, washed with H20 (2 x 25 ml), dried (Na2S04), and the solvent evaporated under reduced pressure to yield the alkyl aryl thioether and the dialkyl disulphide, which can be separated by chromatography from silica. 

A superior and relatively versatile procedure for the synthesis of unsymmetrical dialkyl thioethers, which avoids the unattractive direct use of thiols, utilizes the stable l-alkylthioethaniminium halides, which are readily obtained from thioacet-amidc [32] (Scheme 4.4). The reaction has also been used for the synthesis of alkyl aryl thioethers from activated aryl halides [33], but it cannot be used for the synthesis of cyclic thioethers, as polymeric sulphides are formed from a,co-dihaloalkanes. A similar sequence to that which leads to the thioethers has been used for the synthesis of S-alkyl thioesters [34] (see 4.1.26). 

Diketones react diastereoselectively with the dilithio compounds 475 obtained by the ortho and a-directed metallation of alkyl aryl thioethers and sulfones to give the fra r-thiochroman-3,4-diols and their 1,1-dioxides (Scheme 166) <1998S1098>. o-Bromophenyl sulfones 476 yield the 3,4-disubstituted thiochroman dioxide by a radical cyclization the trans isomer is the predominant or even exclusive product (Equation 160) <1995SL943>. 

Mono- and difluorination of alkyl aryl thioethers under electrooxidative conditions also proceed when the phenyl ring is substituted by strongly electron-withdrawing groups, such as NO2, CN, SO Me, and S02Ph [116] (see Chapter 26). 

This procedure3 is an example of a simple and general method for preparation of primary and secondary dialkyl and alkyl aryl thioethers via alkylation of sodium sulfide or sodium alkyl- or arylthiolates with alkyl chlorides or bromides. The method is an... 

A series of S-substituted aminoalky-lamino ethanethiols, such as, 5 -2(omega-aminoalkylamino)ethyl alkyl/aryl thioethers, were screened for their protective efficacy against dermally applied sulfur mustard in female mice (Pathak et al. 2004). A number of compounds of this class, when administered orally, demonstrated significant protection against sulfur mustard. 

In 2004-2005, we reported direct thioetherification of tautomerizable heterocycles with sulfur nucleophiles via phosphonium coupling to produce biaryl thioethers or alkyl aryl thioethers. Thiophenols are... 

A great advantage of catalyst 24b compared with other chiral Lewis acids is that it tolerates the presence of ester, amine, and thioether functionalities. Dienes substituted at the 1-position by alkyl, aryl, oxygen, nitrogen, or sulfur all participate effectively in the present asymmetric Diels-Alder reaction, giving adducts in over 90% ee. The reaction of l-acetoxy-3-methylbutadiene and acryloyloxazolidinone catalyzed by copper reagent 24b, affords the cycloadduct in 98% ee. The first total synthesis of ewt-J -tetrahydrocannabinol was achieved using the functionalized cycloadduct obtained [23, 33e] (Scheme 1.39). 

This reaction is analogous to 10-16. Primary and secondary alcohols can be converted to alkyl aryl sulfides (ROH RSAr) in high yields by treatment with BU3P and an V-(arylthio)succinimide in benzene. Thioethers RSR can be prepared from an alcohol ROH and a halide R Cl by treatment with tetra-methylthiourea Me2NC(=S)NMe2 followed by NaH. ... 

In addition, Peruzzini et al. developed, in 2007, iridium complexes of planar-chiral ferrocenyl phosphine-thioether ligands that were tested in the hydrogenation of simple alkyl aryl ketones.These complexes were diastereoselec-tively generated in high yields (85-90%) by addition of the corresponding... 

Scheme 8.33 Hydrogenations of alkyl aryl ketones with ferrocenyl phosphine-thioether ligands.

Treatment of a-(benzotriazol-l-yl)alkyl thioethers 831 with ZnBr2 weakens the bond with benzotriazole, and the obtained complex 832 may partially dissociate to thionium cation 835 that can be trapped by even mild nucleophiles. Thus, trimethylsilyl cyanide added to the reaction mixture causes substitution of the benzotriazole moiety by the CN group to give a-(phenylthio)carbonitrile 834. In a similar manner, treatment with allylsilane leads to y,S-unsaturated thioether 833. Addition of species 835 to the double bond of a trimethylsilyl ot-arylvinyl ether followed by hydrolysis of the silyloxy group furnishes (i-(phenylthio)alkyl aryl ketones 836 (Scheme 132) <1996TL6631>. 

The Leuckart Thiophenol Reaction allows the preparation of thiophenols and corresponding thioethers from anilines or their corresponding diazonium salts. The first step is the reaction of an aryl diazonium salt with a potassium alkyl xanthate to give an aryl xanthate, which affords an aryl mercaptan upon basic hydrolysis or an aryl thioether upon warming. 

R e = alkyl, alkoxy, thioether, ester amino, aryl, halogen etc. 

Over MoS3, alkyl and aryl thioethers are hydrogenolyzed to give hydrocarbons, via... 

The main methodologies developed until now for enantioselective oxidation of sulfides are effective only in the oxidation of alkyl aryl sulfoxides. Dialkyl sulfoxides on the other hand are generally oxidized with only poor selectivity. In an attempt to solve this problem, Schenk s group69 recently reported a stereoselective oxidation of metal-coordinated thioethers with DMD. The prochiral thioether is first coordinated to a chiral ruthenium complex by reaction with the chloride complexes [CpRu[(S,S)-chiraphos]Cl], 36. Diastereoselective oxygen transfer from DMD produces the corresponding sulfoxides in high yield and selectivity. The chiral sulfoxides 37 are liberated from the complexes by treatment with sodium iodide. Several o.p. aryl methyl sulfoxides have been obtained by this method in moderate to high ee (Scheme 12). 

Unconjugated thioethers are not reducible in aqueous solution in aprotic solvents alkyl aryl sulfides, ArSR, are reducible at relatively negative potentials ( —2.5 V (SCE)) [118] with C-S cleavage to ArS and R- the latter may be reduced further. Reduction of diphenylsulfide gives equal amounts of benzene and thiophenoxide ion ... 

Savarin, C., SrogI, J., Liebeskind, L. S. A Mild, Nonbasic Synthesis of Thioethers. The Copper-Catalyzed Coupling of Boronic Acids with N-Thio(alkyl, aryl, heteroaryl)imides. Org. Lett. 2002,4, 4309-4312. 

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