Sulfonium perchlorates

See also ALKANETHIOLS, ALKENEBIS(SULFONIUM PERCHLORATES) allyl trifluo-ROMETHANESULFONATES, ARENEDIAZO ARYL SULFIDES BIS(ARENEDIAZO) sulfides, BIS(SULFURDIIMIDES DIAZONIUM SULFATES, DIAZONIUM SULFIDES AND DERIVATIVES METAL AMIDOSULFATES, METAL PHOSPHORUS TRISULFIDES METAL SULFATES, METAL SULFIDES, NON-METAL SULFIDES SULFONIC ACID ESTERS, SULFUR BLACK, SULFUR ESTERS THIOPHENOXIDES, XANTHATES ... 

Alkylation of 2-methoxycarbonyl-l-oxoindane with these sugar-substituted sulfonium salts gives the (/f)-2-alkyl derivatives with enantiomeric excesses up to 12%, while alkylation of ethyl 2-methyl-3-oxobutanoate with allyl or benzyl(aryl)sulfonium perchlorates gives 2-allyl-(or benzyl)-substituted ethyl 2-methyl-3-oxobutanoates 5 with enantiomeric excess up to 25%12. 

Takaki reports that ketone enolates add to dimethylstyryl sulfonium perchlorate (155) or methyl styryl sulfone (156) in a Robinson-type annulation sequence to afford the corresponding 3-hydroxythiadecalin (157) or 5-dioxide (158), respectively subsequent reductive desulfonation of (158) affords diene (159).131 However, additions to acceptor (155) suffer from competing cyclopropanation which is dependent on the electrophilicity of the carbonyl group and the ring size of the ketone (Scheme 61). As an aside, DeLucchi reports that l,l-bis(benzenesulfonyl)ethylene (160) adds to ketones at the more substituted a-carbon under neutral conditions in refluxing acetonitrile (equation 18).132... 

See Trifluoromethanesulfonic acid Perchlorate salts ALKENEBIS(SULFONIUM PERCHLORATES)... 

Alkenebis(sulfonium perchlorates), 15 Alkenes, 15 Alkenyl nitrates, 17... 

The electrooxidation of dibenzothiophene and its 2,8-dimethoxy derivative, performed at Pt electrodes in MeCN/LiC104, with or without lutidine, led to similar results. In the presence of lutidine the product was the corresponding 5-oxide (63%), whereas in the absence of base a sulfonium perchlorate was isolated (61%) [217]. However, the oxidation of 2,4,6,8-tetramethoxydibenzothiophene and 2,3,4,6,7,8-hexamethoxydiben-zothiophene [Eq. (101)] under the same conditions resulted exclusively in a coupling product [217]. 

Dimethyl-(2-carboxy-4-methylphehyl)sulfonium perchlorate boiled 1 hr. with 2 N NaOH —> 2-methylthio-5-methylbenzoie acid. Y 94%. (F. Krollpfeiffer, H. Hartmann, and F. Schmidt, A. 563, 15 (1949) without NaOH s. A. 566, 139 (1950).)... 

Benzenesulfenyl chloride in nitromethane added to 5 eqs. each of LiC104 and dimethyl sulfide in the same solvent, the precipitated LiCl removed, 0.5 eq. 2,3-dimethylbut-2-ene added at 0-5, and left for 10 h - dimethyl(2,3-dimethyl-2-butenyl)sulfonium perchlorate. Y ca. 90%. F.e. and arenesulfenyl chlorides s. I.V. Bodrikov et al., Zh. Org. Khim. 24, 1107-8 (1988). 

Unsym. sulfonium perchlorates can be efficiently prepared from sulfides and alcohols with perchloric acid. The non-nucleo-philic nature of the perchlorate ion as compared to the halide ion makes the process irreversible and avoids alkyl interchange... 

A mixture of di-n-butyl sulfide, 70%-perchloric acid, and benzyl alcohol heated 4 hrs. at 70-80 benzyldi-(n-butyl) sulfonium perchlorate. Y 83.5%.—The non-nucleophilic nature of perchlorate ion as compared to halide ion makes the process irreversible and thus avoids alkyl interchange. F. e., also with azeotropic removal of water, s. T. W. Milligan and B. G. Minor, J. Org. Ghem. 28, 235 (1963). 

Startg. cyclic sulfonium perchlorate heated at 90° with l,8-diazabicyclo[5.4.0]-undec-7-ene in toluene cw-product. Y 67% (and 7% rran -isomer). - S-Macro-heterocyclics by repetition of this 2,3-sigmatropic shift s. E. Vedejs and J. P. Hagen, Am. Soc. 97, 6878 (1975). 

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