Substituted methyl phenyl sulfoxides

A combination of the Pummerer rearrangement and the Ritter reaction occurs in the reaction of acetonitrile with methyl phenyl sulfoxide (equation 25) in a mixture of irifluoroacetic acid and its anhydride, although a substantial amount of the nonnal a-acetoxylation also occurs. Participation by amido groups is also possible, the interest here being largely in the construction of lactams via the intramolecular cycli-zation mode. Whereas Wolfe and his coworkers were unable to find conditions for the cyclization of S-phenylcysteinamide sulfoxides under Pummerer conditions, Kaneko found that variously substituted... 

Both complexes were able to catalyze the oxidation of jt-substituted methyl phenyl sulfides at a substrate/catalyst molar ratio of 100, with good sulfoxide selectivities (> 90%). It should be noted that FB reactions catalyzed by Mn-14 consistently afforded higher sulfoxide yields than homogeneous reactions catalyzed by Mn-13 (Table 4). Moreover, three consecutive recyclings of the fluorous layer were performed with no appreciable loss of catalytic activity and selectivity. 

Methyl phenyl sulfide was stoichiometrically converted to the corresponding sulfoxide by MP-11 based on H2O2 in 50% methanol-aqueous solution ). The relative reactivities of p-substituted methyl phenyl sulfide correlated well with the Hammett Gp+ values. The sufide oxidation with H2 02 gave completely l O-labeled methyl phenyl sulfoxide, which indicated that the oxygen atom had originated from iron-oxenoid active species, as it does with peroxidases and cytochrome P-45Q2). 

Enantiomerically pure methyl phenyl sulfoxide and methyl p-tolyl sulfoxide in diethyl ether or dimethoxyethane were reacted with alkyllithium reagents. The exchange reactions were found to proceed with inversion of configuration at sulfur. The yields are somewhat variable, but Johnson s work did indicate that special procedures are necessary for the generation of hthium a-sulfinyl carbanions for use in other synthetic purposes for example, Johnson recommended the use of lithium dialkylamides as bases, since nucleophilic substitution can occur either on the neutral molecule or on the carbanion with alkyllithium reagents. 

A useful survey of the chemistry of phosphite radicals, prepared by pulse radiolysis, has been presentedThese can take part in oxidation, reduction, substitution, and addition reactions. Reports have been published on the oxidation by peroxodiphosphate of alkyl aryl sulfides,methyl phenyl sulfoxide,and hexacyanoferrate(II). The oxidation of dialkyl sulfides by peroxomonophos-... 

Isoquinolinones could also be formed from the annulation reactions of o-substituted Af-benzoylated sulfoximine and diphenylacetylene via Ru(II)-catalyzed redox-neutral C-H bond functionalization (Eq. (7.42)) [52]. As a result, the formation of methyl phenyl sulfoxide was observed, and the methyl phenyl sulfoximine directing group can be regenerated. 

Molecules having only a sulfoxide function and no other acidic or basic site have been resolved through the intermediacy of metal complex formation. In 1934 Backer and Keuning resolved the cobalt complex of sulfoxide 5 using d-camphorsulfonic acid. More recently Cope and Caress applied the same technique to the resolution of ethyl p-tolyl sulfoxide (6). Sulfoxide 6 and optically active 1-phenylethylamine were used to form diastereomeric complexes i.e., (-1-)- and ( —)-trans-dichloro(ethyl p-tolyl sulfoxide) (1-phenylethylamine) platinum(II). Both enantiomers of 6 were obtained in optically pure form. Diastereomeric platinum complexes formed from racemic methyl phenyl (and three para-substituted phenyl) sulfoxides and d-N, N-dimethyl phenylglycine have been separated chromatographically on an analytical column L A nonaromatic example, cyclohexyl methyl sulfoxide, did not resolve. 

Oae and Khim measured the rates of hydrolysis of chlorophenyl phenyl sulfoxides and sulfones with hydroxide ion in aqueous DMSO at 158 °C. Both SOPh and S02Ph were found to activate the nucleophilic substitution from ortho- and para-positions, but the effect of SOjPh was considerably larger than that of SOPh. The results were interpreted in terms of 7t(pd) conjugation in the intermediate complexes. In a later paper it was shown that the introduction of a methyl group ortho to SOPh or S02Ph slightly retards the above and related reactions but this was attributed to the inductive effect of Me rather than steric inhibition of 7t(pd) conjugation (Section III.A.l). 

Asymmetric synthesis of sulfoxides can be achieved by biocatalytic oxidation of sulfides and reduction of sulfoxides (Figure 33). i4-27s One example is the reduction of alkyl aryl sulfoxides by intact cells of Rhodobacter sphaeroides f.sp. denitrificans (Figure 33 (a)). 341 In the reduction of methyl -substituted phenyl sulfoxides, ( S )-cnanliomcrs were exclusively deoxygenated while enantiomerically pure (W)-isomcrs were recovered in good yield. For poor substrates such as ethyl phenyl sulfoxide, the repetition of the incubation after removing the toxic product was effective in enhancing the ee of recovered (f )-enantiomers to 100%. 

On the basis of the electronic structure of the sulfur atom, the poly( phenylsulfonium cation) should be employed as a precursor. We have communicated a preliminary successful attempt to synthesize PPS via a soluble poly[methyl[4-(phenylthio)phenyl]sulfonium cation] intermediate (eq 3)(5i,52). The process involves the self-condensation of methyl 4-(phenylthio)phenyl sulfoxide in acid by an electrophilic substitution reaction at room temperature. 

Melles and Backer " found, from a study of the oxidation of substituted thiophenes with perbenzoic or peracetic acid, that sulfones could be obtained from polysubstituted methyl- and phenyl-thiophenes and that the presence of electron-attracting groups, such as nitro, hindered the oxidation. Oxidation of thiophene - led to a product which was formed through a Diels-Alder reaction between the intermediate thiophene sulfoxide (211) and thiophene sulfone (212) and for which two alternative structures, (213) or (214), were suggested. Similar sesquioxides were also obtained from 2- and 3-methylthiophene and 3-phenylthiophene. The structures were not proved. Bailey and Cummins synthesized thiophene-1,1-dioxide... 

Abbreviations aapy, 2-acetamidopyridine Aik, alkyl AN, acetoniuile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene COE, cyclooctene COT, cyclooctatetraene Cp, cyclopentadienyl Cp , penta-methylcyclopentadienyl Cy, cyclohexyl DME, 1,2-dimethoxyethane DME, dimethylformamide DMSO, dimethyl sulfoxide dmpe, dimethylphosphinoethane dppe, diphenylphosphinoethane dppm, diphenylphosphinomethane dppp, diphenylphosphinopropane Et, ethyl Ec, feirocenyl ind, inda-zolyl Me, methyl Mes, mesitylene nb, norbomene orbicyclo[2.2.1]heptene nbd, 2,5-norbomadiene OTf, uiflate Ph, phenyl PPN, bis(triphenylphosphoranylidene)ammonium Pi , propyl py, pyridine pz, pyrazolate pz, substituted pyi azolate pz , 3,5-dimethylpyrazolate quin, quinolin-8-olate solv, solvent tfb, teti afluorobenzobaiTelene THE, tetrahydrofuran THT, tetrahydrothiophene tmeda, teti amethylethylenediamine Tol, tolyl Tp, HB(C3H3N2)3 Tp , HB(3,5-Me2C3HN2)3 Tp, substituted hydrotiis(pyrazol-l-yl)borate Ts, tosyl tz, 1,2,4-triazolate Vin, vinyl. 

For the addition of ethylene, EtOAc as solvent was particularly advantageous and gave 418 in 60% yield (Scheme 6.86). The monosubstituted ethylenes 1-hexene, vinylcyclohexane, allyltrimethylsilane, allyl alcohol, ethyl vinyl ether, vinyl acetate and N-vinyl-2-pyrrolidone furnished [2 + 2]-cycloadducts of the type 419 in yields of 54—100%. Mixtures of [2 + 2]-cycloadducts of the types 419 and 420 were formed with vinylcyclopropane, styrene and derivatives substituted at the phenyl group, acrylonitrile, methyl acrylate and phenyl vinyl thioether (yields of 56-76%), in which the diastereomers 419 predominated up to a ratio of 2.5 1 except in the case of the styrenes, where this ratio was 1 1. The Hammett p value for the addition of the styrenes to 417 turned out to be -0.54, suggesting that there is little charge separation in the transition state [155]. In the case of 6, the p value was determined as +0.79 (see Section 6.3.1) and indicates a slight polarization in the opposite direction. This astounding variety of substrates for 417 is contrasted by only a few monosubstituted ethylenes whose addition products with 417 could not be observed or were formed in only small amounts phenyl vinyl ether, vinyl bromide, (perfluorobutyl)-ethylene, phenyl vinyl sulfoxide and sulfone, methyl vinyl ketone and the vinylpyri-dines. 

Nucleophilic substitution of the chlorine atom present in 2-chlorothiepane (132) using Grignard reagents has provided a synthetic route to 2-methyl- (133) or 2-phenyl- (134) thiepanes (equation 27) (69JHC115). An a-sulfinyl carbanion (114), generated by alkyllithium attack on thiepane 1-oxide (115), was found to act as nucleophile in the synthesis of cis and trans sulfoxides of thiepane (133 equation 28) (78TL5239). Polymerization of 2-thiepanone (135) has been initiated by attack of the f-butoxide anion and concomitant liberation of a thiolate anion (Scheme 26) (64MI51700). 

---