Aralkyl sulfides

Iron porphyrin catalysts with TBHP have been used for the diastereoselective oxidation of sulfides affording up to 46% d.e.408 A series of manganese(salen) catalysts with hydrogen peroxide has been employed for the oxidation of aralkyl sulfides in 34-70% d.e. and 80-90% yield. The best catalyst was derived from enantiomerically pure trans-1,2-diaminocyclohexane (Figure 3.101).409... 

As a terf-aralkyl sulfide, 5-trityl (Trt)t 29i protection became important in peptide chemistry only upon discovery of its quantitative cleavage with metal ions,t l or by oxidative iodinolysis, as well as upon the development of optimized scavengers capable of preventing retritylation of the thiol group under acidic conditions,t l particularly when trialkylsilanes are included as scavengers.Further enhancement of the acid lability of 5-trityl was obtained, as expected, with the 4-methoxytrityl (Mmt) group (Scheme 11).P 36]... 

Qualitative work on the photolysis of a number of alkyl aralkyl sulfides indicates that the observed products arise from radical reactions of aromatic and thiyl free radicals formed in the primary process. In the case of ethyl a-methylbenzyl sulfide an intramolecular reaction was proposed... 

Thiocarbonyl Compounds Aliphatic thials or thi-ones exist as trimeric, cyclic sulfides. Aralkyl thiones... 

PhCH2), obtained in their turn by treatment of 3-alkyl(or aralkyl) thio-5-chloro-l,2,4-thiadiazoles (344 R = Me or PhCH2) with ammonium sulfide.91 Additional support in favor of structure 340 for perthiocyanic acid is the alternative production of its disodium salt (343) from 5-chloro-3-mercapto-l,2,4-thiadiazole (344 R = Na) and sodium sulfide.151... 

Thiocarbonyl Compounds Aliphatic thials or thiones exist as trimeric, cyclic sulfides. Aralkyl thiones may exist either as monomers or trimers, whereas diaryl thiones, such as thiobenzophenone, exist only as monomers. The C=S group is less polar than the C=0 group and has a considerably weaker bond. In consequence, the band is not intense, and it falls at lower frequencies, where it is much more susceptible to coupling effects. Identification is therefore difficult and uncertain. 

Partial desulfurization. Disulfides (cyclic, benzylic, aralkyl, and dialkyl) are converted into sulfides by reaction with the reagent at 25-80°.3 For example, when dibenzyl disulfide is treated with a 10% excess of the phosphine in refluxing benzene... 

Reaction with Sulfoxides. DAST reacts with a-hydrogen containing dialkyl and aralkyl sulfoxides to form a-fluoroalkyl sulfides in high yields (eq 17). This reaction can be extended to less reactive sulfoxides by catalysis with certain Lewis acids, e.g. Antimony(IU) Chloride (eq 18) and Zinc IodideP... 

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