Ethyl sulfoxide

Methyl m-tolyl (8), ethyl m-tolyl, methyl n-butyl and methyl n-propyl sulfoxides were obtained in 100% e.e. This method was less successful when applied to methyl phenyl sulfoxide (5% e.e.) or to methyl isobutyl and methyl ethyl sulfoxides (25% e.e.). No complexes were formed between methyl o-tolyl, methyl p-tolyl, methyl 2-butyl and methyl isopropyl sulfoxides so these compounds could not be resolved using 7. A crystal structure of the 1 1 complex formed between 7 and 8 revealed that the partners were linked by OH—OS hydrogen bonds in endless zig-zag chains23. More recently, 2-chloroethyl m-tolyl sulfoxide (9) has been resolved using 724. 

Some additions and corrections have been made. The data given here for f-butyl ethyl sulfoxide were not included in either Cox and Pilcher16 or Pedley, Naylor and Kirby17. The latter authors give data for a compound identified as ethyl methyl sulfate (sulfuric acid ethyl methyl ester), which is identified in Cox and Pilcher16 and in the original article23 as... 

Closely related procedures are based on z-a I kyIthiosu Ifoxidcs, with ethylthiomethyl ethyl sulfoxide being a particularly convenient example.119 120... 

It is known that cyclodextrins have a hydrophobic cavity (a binding site for aromatics) and a hydrophilic external surface. A template-directed asymmetric sulfoxidation has been attempted with various aryl alky] sulfides [91]. Oxidations were performed by using metachlo-roperbenzoic acid in water in the presence of an excess of (3-cyclodextrin. The best ee (33%) was attained for meta- r-butyI)phenyl ethyl sulfoxide. The decrease in the amount of P-cyclodex-trin below 1 mol equiv. causes a sharp decrease in enantioselectivity because of competition with oxidation of free substrate by the oxidant. Similarly, DrabowiczandMikolajczyk observed modest asymmetric induction (27% ee) in the oxidation of Ph-S-n-Bu with H202 in the presence of P-cyclodextrin [92],... 

Adipic acid a-Alanine Allyl ethyl sulfoxide Allyl trichloroacetate... 

The synthesis of both isomers of a given sulfoxide can be achieved via the Orsay route by permutation of the R, and R2 in organometallics involved in the two substitution steps, and has been done in the synthesis of o.p. R and 5 methyl octyl sulfoxide and benzyl ethyl sulfoxide. This is possible only when both R, and R2 are either small or bulky—when one of the groups is small and the other bulky, the permutation leads to the same sulfoxide. 

Figure 8. Chiral methyl and ethyl sulfoxides of interest as synthetic intermediates.

Palladium-catalyzed annulation of the thioether 26 with various alkenes has been demonstrated to furnish the tricyclic systems 27 in modest yields <07JOC775>. Formation of 2,3-dihydrobenzo[Z>]thiophenes has also been observed upon fluoride induced rearrangement of certain aryl 2-(trimethylsilyl)ethyl sulfoxides <07OBC1595>. 

Alkenylstannanes. Aryl ethyl sulfoxides are converted to (l-arylthiovinyl)tributyl-... 

Eliminations. When functionalized silanes in which a potential leaving group is attached to a /3-atom or to a vinylogously related atom are treated with TBAF, fragmentation ensues. New uses of this process are preparations of 2,3-dimethylene-2,3-dihydrothiophene," substituted 1,2,3-butatrienes, chiral allylic alcohols, and a-fluoroketones. The precursors for the allylic alcohols are the alkylation products (with aldehydes) of 2-(trimethylsilyl)ethyl sulfoxides, and those for the fluoroketones are 1-silyl-l-hydroxymethyloxiranes. 

Preparation of Ethylthiomethyl Ethyl Sulfoxide and Methyl Phenyl Sulfoxide... 

Benzyl ethyl sulfide allowed to react with 1,4-diazabicyclo [2.2.2] octane bromine complex in aq. 70%-acetic acid benzyl ethyl sulfoxide. Y 95%. — The reaction is very rapid. The products are completely free from sulfones. Neither cleavage of aliphatic G-S-bonds, which may occur when N-bromosuccinimide is used, nor ar. bromination, when bromine is used, has been observed. F. e., also O-labeled sulfoxides with 0-enriched water, and use of bromine complexes with pyridine and quinoline, s. S. Oae et al.. Bull. Ghem. Soc. Japan 39, 364 (1966). 

An aq. soln. of (+)-4-(l-j -D-glucosyloxy)phenylethyl sulfoxide (obtained from the diastereomeric mixture by crystallization) containing phosphate buffer (pH 5) treated with a mixture of emulsin and kieselguhr, kept at 37 until paper chromatography shows completion of the cleavage -> (+)-4-hydroxy-phenyl ethyl sulfoxide. Y 80-90%. F. e. s. G. Wagner and S. Bohme, Arch. Pharm. 297,257 (1964). ... 

C17H20O2S, Methyl (2-hydroxy-2-pheny1-2-(2, 4 -dimethylpheny1))ethyl sulfoxide, 40B, 87... 

An analogous free radical displacement reaction is observed at sulfoxide centers, but fails for the corresponding sulfone. Thus, photolysis of methyl 2-(o-iodophenyl)ethyl sulfoxide (X, R=CH3) in cyclohexane gives methyl 2-phenylethyl sulfoxide (XI, R=CH3) and dihydrobenzothiophene oxide (XII)(eq. 5). Photolysis of ethyl(2-o-iodophenyl)ethyl sulfone in... 

PRODUCTS OF PHOTOLYSIS OF ALKYL 2-(o-IODOPHENYL) ETHYL SULFOXIDES (X) IN CYCLOHEXANE... 

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