Sulfinates, alkyl phenyl

Cyclodextrins, toroidal molecules composed of 6, 7 and 8 D-gJucose units, are now commercially available at reasonable cost. They form inclusion compounds with a variety of molecules and often differentially include sulfoxide enantiomers . This property has been used to partially resolve some benzyl alkyl, phenyl alkyl and p-tolyl alkyl sulfoxides. The enantiomeric purities after one inclusion process ranged from 1.1% for t-butyl p-tolyl sulfoxide to 14.5% for benzyl t-butyl sulfoxide. Repeating the process on methyl p-tolyl sulfoxide (10) increased its enantiomeric purity from 8.1 % to 11.4% four recrystallizations raised the value to 71.5%. The use of cyclodextrins in asymmetric oxidations is discussed in Section II.C.l and in the resolution of sulfinate esters in Section II.B.l. 

Keywords alkyl halide, sodium phenyl sulfinate, alkylation, alumina, microwave irradiation, sulfone... 

For methyl phenyl sulfoxide it was found that 25% of the adduct decomposes to give phenyl radical and methane sulfinic acid, while 75% of the adduct leads to methyl radical and benzene sulfinic acid. For heavier alkyl groups the formation of the benzene sulfinic acid is even more dominant, 96% for R = Et and 100% for R = C2H4C1 or i-Pr. 

Pedersen and coworkers investigated the El mass spectra of several 2-hydroxyphenyl alkyl sulfones (39) and sulfoxides (Section II.B). The methyl derivative seemed to fragment only via sulfinate ester formation giving the primary product ions m/z 157 and 109 (equation 14). Obviously hydrogen bonding between the ortho hydroxyl and the sulfone sulfur makes the loss of CH3SO2 difficult in contrast to the situation in methyl phenyl sulfone. The sulfinate ester rearrangement is not important when R>Et in 39. 

These are good dienophiles. and aryl vinyl sulfones have found use as equivalents of ethylene and ketene through functional modifications of their adducts. However, as the base-induced elimination of a sulfinic acid to yield an olefin occurs only with difficulty, they are not direct precursors of acetylene equivalents, unless suitably modified as in ( )-l-phenyl-sulfonyl-2-trimethylsilyl ethylene (PhS02-CH=CH-TMS). In its cycloadducts the elimination to an alkene is smoothly realized by the fluoride ion. If an alkylation step is previously carried out on the adduct, the overall process realizes an indirect addition of a terminal acetylene, as in the examples given here [533]. 

The mixture of sodium phenyl sulfinate (6.566 g, 40 mmol) and neutral chromatographic alumina (20 g) was evaporated with a rotary evaporator under vacuum. The solid was dried 2 h at 110°C under vacuum. The alkyl halide (5 mmol) was absorbed onto sodium phenyl sulifinate on alumina (6.6 g, 1.52 mmol of sodium phenyl sulfinate). The mixture was irradiated by microwave (160 W, 5 min). After cooling at room temperature the mixture was extracted with acetonitrile. The product was recrystallized in ethanol after evaporation of solvent. 

Cheng et al. [316] synthesized the polymer-bound 2-sulfony-l, 3-dienes from the corresponding support-bound suhblene, which upon thermal S02-extrusion gave the highly reactive diene (345), which could be trapped with dienophiles. The synthesis on a polystyrene support begins with polymer-bound lithium phenyl-sulfinate. S-Alkylation with trans-3, 4-dibromosulfolane (343) in the presence of pyridine gave the resin-bound 3-(phenylsulfonyl)-3-sulfolene. Thermal SO2 extrusion had to be performed in xylene under reflux, which restricts the use of this reaction to PS/DVB-resins. Neither the IRORY-Kans [317] nor the Synphase Crowns [199], which are made of polypropylene, are compatible with these reaction conditions, in which polypropylene is dissolved (Scheme 72) ... 

The phenylsulfinyl fluoroacetate can be alkylated with a wide range of alkyl halides and Michael acceptors. Subsequent thermal elimination of phenyl sulfinic acid leads to a-fluoro-a,p-unsaturated ethyl carboxylates, an important class of intermediates for fluorine containing biologically active compounds [19] (Scheme 5.4). 

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