Sulfoxide, chloromethyl phenyl

Addition of BuLi to a 0.3 M solution of chloromethyl phenyl sulfoxide in THF at — 78 "C yields an immediate bright-yellow solution containing the lithio derivative which is stable for at least 2 h at —78 rC. Decomposition occurs rapidly above —20 C with the solution becoming turbid and the color changing to dark brown. Reaction of the lithiated solution of chloromethyl phenyl sulfoxide with cyclohexanone, acetone, or ben/ophenone for 10 min at —78 °C followed by 30 min at —20 rC yields one diastereomeT in 79, 75 and 68 % yields, respectively, after hydrolysis of the corresponding adducts. 

E. Reduction of Halomethyl Phenyl Sulfones and Chloromethyl Phenyl Sulfoxide by Fluorenide Anions... 

In 1993, Satoh and coworkers reported the preparation of lithium- and magnesium-aUtylidene carbenoids from 1-chlorovinyl phenyl sulfoxides by sulfoxide-metal exchange reaction at low temperature (Scheme 6). 1-Chlorovinyl phenyl sulfoxide (128) is easily synthesized from the corresponding aldehyde and chloromethyl phenyl sulfoxide in high yield. Sulfoxide 128 was treated with f-BuLi in THF at —78 °C to give the terminal alkyne 131. Obviously, the intermediate of this reaction was the alkylidene carbenoid 129. 

The lithium anion of chloromethyl phenyl sulfoxide reacts with tetrahydrofuran-2-ones 1011 to afford a diastereo-meric mixture of hemiacetal adducts 1012, the potassium enolate of which is treated with /-BuLi followed by addition of a proton source leading to to-hydroxyalkyl ketenes 1013, which themselves cyclize to 6-substituted tetrahydropyran-2-ones in excellent overall yield (Scheme 263) <1998TL9215>. 

Ketone synthesis. The reaction of NaScQ.H, (excess) with a,p-cpoxy sulfoxides, available by reaction ol aldehydes or ketones with the anion of chloromethyl phenyl sulfoxide (8, 94-95), results in a-substituted ketones and diphenyl disclenide. 

Lithiochloromethyl phenyl sulfoxide, CeHsSCHClLi. The anion is generated from chloromethyl phenyl sulfoxide by reaction with LDA in THF at —78°. 

The a-chloro-a-sultinyl ketone 20 was prepared from methyl benzoate and chloromethyl phenyl sulfoxide 19 after in situ a-lithiation. Compound 20 is dimetallated by KH and f-BuLi to give the keto dianion 21, which is converted into a potassium/lithium ynolate 22 (equation 7). The resulting metal ynolates are converted into thioesters, carboxylic acids, amides and esters (Section V). 

Durst reported that lithiation of chloromethyl phenyl sulfoxide (99) with butyllithium followed by treatment of a symmetrical ketone (-78 °C to -20 C) affords an adduct (100). This reaction is so highly stereoselective that only one diastereomer is produced. Reaction of (100) with dilute methanolic KOH gives an epoxy sulfoxide (101 equation 25). - °... 

When chloromethyl phenyl sulfone (130 Ar = phenyl) was subjected to the Darzens-type reaction with an aldehyde, a thermodynamically stable trans isomer (133) was produced exclusively (equation 32). This is in sharp contrast with the corresponding reaction of chloromethyl phenyl sulfoxide. Tavares proposed that the initial nucleophilic attack of the a-sulfonyl carbanion upon a carbonyl compound is rapidly reversible due to its stability, and that the product-determining step is the ring closure. Thermodynamic equilibrium between the two diastereomers of (132) allows predominant formation of the thermodynamically stable isomer (133) from the preferred transition state. ... 

Ring expansion of lactones by reaction of the latter with lithiated chloromethyl phenyl sulfoxide with subsequent treatment with KH and then f-BuLi is a mechanistically intriguing transformation. Episulfone is readily deprotonated. Tris(trimethylsilyl)episulfone has been obtained. A convenient synthesis of trimethylsilylmethyl isocyanate is by Hthiation of... 

The carbene precursor is synthesized by the reaction of diazomethane with phenylsulfenyl chloride, and due to its instability it is not purified, but used as a mixture with chloromethyl phenyl sulfoxide. 

Acetylenes from 1-chlorovinyl sulfoxides. This high-yield conversion (Fritsch-Wiechell rearrangement) terminates a one-carbon homologation of aldehydes. The method consists of condensation of an aldehyde with chloromethyl phenyl sulfoxide and dehydration prior to the treatment with BuLi. 

Homologation of acids (esters). a-Chloro-a-phenylsulfinyl ketones are the condensation products of esters with chloromethyl phenyl sulfoxide. On treatment with t-BuLi-KH these ketones are converted to potassium alkynoxides, which can be transformed into acids through hydration. 

Chloromethyl phenyl sulfoxide, CoH. SCHaCl. Mol. wt. 174.66, m.p. 35 36°. The sulfoxide is obtained in > 70% yield by oxidation of chloromethyl phenyl sulfide with i-chloroperbenzoic acid. ... 

Chloromethyl ketones, 94-95 Chloromethyl methyl ether, 387 Chloromethyl methyl sulfide, 94 Chloromethyl phenyl sulfide, 94 Chloromethyl phenyl sulfoxide, 94-95 2-ChIoro-l-methylpyridinium iodide, 95-96... 

A soln. of chloromethyl phenyl sulfoxide in tetrahydrofuran allowed to react at -78° with -butyllithium, then with cyclohexanone at -78° for 10 min. and at -20° for 0.5 hr. -> adduct (Y 79%) treated 10 min. at room temp, with dil. methanolic KOH -> a-epoxy sulfoxide (Y > 90%). - Formation of the adduct is highly stereospecific. The ease of intramolecular displacement of chloride ion from the adduct contrasts with the great difficulty in displacing chloride ion from chloromethyl phenyl sulfoxide by external nucleophiles. F. e. s. T. Durst, Am. Soc. 91, 1034 (1969) a-chloro-a-lithiumsulfonic acid derivatives s. W. E. Truce and L. W. Christensen, Tetrah. Let. 1969, 3075 syntheses with dichloromethyllithium s. G. Kobrich and W. Werner, Tetrah. Let. 1969, 2181. 

A one-carbcMi ring enlargement approach for the synthesis of 8-lactones has been developed by Satoh and Kurihara [123] (Scheme 76). Reaction of the lithium carbanion of chloromethyl phenyl sulfoxide with lactone 336 afforded a diastereo-meric mixture of the hemiacetal 337. Treatment of this adduct with three equivalents of KH in THF generated potassium enolate 338, which on addition of four equivalents of t-BuLi underwent an alkylidene carbenoid rearrangement to give alkynolate 339. Protonation of 339 by the addition of sulfuric acid facilitated the formation of m-hydroxy ketene 340, which underwent an intramolecular cyclization to afford 8-lactone 341. 

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