Lithium benzenethiolate

Bromo-2-(t-butylsulfonyl)propene (79) reacts with nucleophiles such as lithium benzenethiolate, lithium enolates and Grignard reagents to give a, /(-unsaturated sulfones, which undergo nucleophilic addition of lithium cuprates (equation 68)58. 

The reaction of elemental sulfur with organometallic compounds is one of the standard methods of synthesis of thiols [3, 4], In this way, the ortho lithiation of lithium benzenethiolate led to the preparation of 1,2-benzenedithiol (1), and a convenient one-pot procedure which can be used on a large scale was worked out [5]. 

Diethylaluminum phenylthiolate (l).1 The reagent is prepared from triethyl-aluminum and thiophenol and is used without isolation. The alumi um reagent reacts regio- and stereoselectively with vinyl epoxides (2) to afford mainly (Z)-4-phenylthio-2-butene-l-ol derivatives (3). In contrast reaction of vinyl epoxides with C6H5SH and N(C2H5)3 gives mainly the (E)-isomer. Lithium benzenethiolate does not cleave vinyl epoxides at 25°. 

The three-component reaction of lithiated [bis(phenylsulfanyl)methyl]trimethylsilane, phenyloxirane, and an alkene takes an interesting reaction pathway. Obviously the oxirane serves as a trapping reagent for lithium benzenethiolate, which results from a-elimination of the initially formed organolithium compound. The generated phenylsulfanyl(trimethylsilyl) carbene (4) adds stereoselectively to various alkenes. In all cases the sterically less crowded Z-isomer cyclopropane 5 is formed. 

Michael-aldol reaction tandem. Addition of lithium benzenethiolate to conjugated esters in the presence of aldehydes is followed by an aldol reaction in a stereoselective manner. 

Butenolides.—A simple-looking route to 2-substituted butenolides involves conjugate addition of lithium benzenethiolate to but-2-en-4-olide in the presence of an aldehyde (Scheme 13). Yields are quite good for the four examples discussed but unfortunately the reaction fails with ketones. 

Various substituted difliorodipyridoimidazoles 153-158 have been synthesized on the basis of obtained dipyridoimidazole 146 [116], All reactions of 146 with nucleophiles gave products arising from selective displacement of fluorine located at the C-1 position. Reaction with only one equivalent of lithium benzenethiolate... 

The intermediacy of cyclohexyne or cyclopentyne in the decomposition of, respectively, 2-fluoro- or 2-chloro-l-cyclohexenyllithium and 2-bromo-l-cyclopentenyllithium is hypothetical. The adducts obtained upon treatment with phenyllithium and lithium benzenethiolate may result from an addition/elimination rather than from an elimination/addition sequence. The reaction order, a kinetic gold standard, is not the same in DEE and THF. Moreover, whatever the number, it is treacherous as long as the aggregation state of the organolithiums is unknown. 

The bicyclo[2.2.0]but-l(3)-enes belong to the latter class. As systematic investigations by Gunter Szeimies have disclosed, tricyclo[4.1.0.0 ]hept-l(7)-ene acts as a turntable in the reactions of alkyl- and aryllithiums with 1-chlorotricyclo[4.1.0.0 ]heptanes (Scheme 1-219). Lithium aziridine is basic enough to sustain such a sequence of metaiation, elimination, and nucleophilic addition. The A-tricycloheptylaziridine thus formed thermolyses at 150 °C to cyclohex-2-ene-l-carbonitrile. The weekly basic lithium benzenethiolate requires the assistence of LITMP to accomplish the deprotonation step before it can add smoothly to give the intermediate 276 (Scheme 1-219). Dienes rather than nucleophiles may be also used to trap strained bicyclo[2.2.0]but-l(3)-enes like 276. Such species may also be generated from l-bromo-7-(trimethylsilyl)tricyclo[4.1.0.0 ]heptanes and cesium fluoride in DMSO at +25 °C. At elevated temperatures (about +100 °C), the bicyclobutene 276 isomerizes rapidly to 1,3,5-cycloheptatriene by [2+2]-cycloelimination. ... 

Thiophenol, lithium salt [Benzenethiol, lithium salt], 55, 122 Toluene, 4-bromo- [Benzene, 1 bromo 4 methyl-], 55, 49... 

Benzenesulfonyl chloride, 4-methyl- [p-Tol-uenesulfonyl chloride], 55, 57, 59 Benzenethiol [Phenol, thio-], 55, 122 Benzenethiol, copper(I) salt [Thiophenol, copper(I) salt], 55, 123 Benzenethiol, lithium salt [Thiophenol, lithium salt], 55, 1 22 Benzoic acid, 2-amino- [Anthramlic acid], p bromination of, 55, 23... 

A comparison of the suitability of solvents for use in Srn 1 reactions was made in benzenoid systems46 and in heteroaromatic systems.47 The marked dependence of solvent effect on the nature of the aromatic substrate, the nucleophile, its counterion and the temperature at which the reaction is carried out, however, often make comparisons difficult. Bunnett and coworkers46 chose to study the reaction of iodoben-zene with potassium diethyl phosphite, sodium benzenethiolate, the potassium enolate of acetone, and lithium r-butylamide. From extensive data based on the reactions with K+ (EtO)2PO (an extremely reactive nucleophile in Srn 1 reactions and a relatively weak base) the solvents of choice (based on yields of diethyl phenylphosphonate, given in parentheses) were found to be liquid ammonia (96%), acetonitrile (94%), r-butyl alcohol (74%), DMSO (68%), DMF (63%), DME (56%) and DMA (53%). The powerful dipolar aprotic solvents HMPA (4%), sulfolane (20%) and NMP (10%) were found not to be suitable. A similar but more discriminating trend was found in reactions of iodobenzene with the other nucleophilic salts listed above.46 Nearly comparable suitability of liquid ammonia and DMSO have been found with other substrate/nucleophile combinations. For example, the reaction of p-iodotoluene with Ph2P (equation (14) gives 89% and 78% isolated yields (of the corresponding phosphine oxide) in liquid ammonia and DMSO respectively.4 ... 

Hydrazine, lithium triethylborohydride, and sodium benzenethiolate produced the tellurium halides only in low yields3. 

The complex Os(SCl0Hl3)4(CNMe) is made from OsCl3, the lithium salt of 2,3,5,6-tetramethyl-benzenethiolate and 2,3,5,6-tetramethylphenyl sulfide it is green-yellow. The X-ray crystal structure of the ruthenium salt shows it to be trigonal bipyramidal, with the acetonitrile in the axial position. The osmium complex is isomorphous it would seem therefore to be the only example so far reported of a trigonal bipyramidal osmium(IV) complex. In an attempt to make a complex of lower coordination number 2,4,6-triisopropylbenzenethiolate (SC15H23) was used but the complex was still pentacoordinate, i.e. Os(S15H23)4(MeCN).719... 

Reduction of l,4-diacetyl-5,6-diphenyl-l,2,3,4-tetrahydropyrazine with lithium aluminum hydride formed l,4-diethyl-5,6-diphenyl-l,2,3,4-tetrahydropyrazine (1562). Both l,4-dibenzenesulfonyl-2-hydroxy-l,2,3,4-tetrahydropyrazine and l,4-dibenzenesulfonyl-2,5-dihydroxypiperazine reacted with hot acidic methanol to produce l,4-dibenzenesulfonyl-2-methoxy-l,2,3,4-tetrahydropyrazine (1602). The tosyl analogue behaved similarly. Reaction of 2-hydroxy-l,4-ditosyl-l,2,3,4-tetrahydropyrazine (73, X = OH) with benzenethiol in acidified acetone gave 2-phenylthio-l,4-ditosyl-l,2,3,4-tetrahydropyrazine (73, X = SPh) (1602). 

A procedure similar to that described for Section 9-A may be used to prepare this compound from lithium (0.28 g, 40 mmole), benzenethiol (4.1 mL, 40 mmole), iron(III) chloride (1.62 g, 10 mmole), selenium powder (0.79 g, 10 mmole), and tetrabutylammonium iodide (2.77 g, 7.5 mmole). The black precipitate should be collected by filtration, washed copiously with methanol, and dried in vacuo. This solid can be recrystallized by dissolution in the minimum volume of acetonitrile at 45°, adding methanol to incipient crystallization at this temperature and allowing the solution to cool slowly to room temperature before leaving it overnight at ca. -5°. The compound (2.9 g, 80%) crystallizes as large, black prisms. 

Benzenethiol, copper(I) salt, 55, 123 Benzenethiol, lithium salt, 55, 122... 

The scope of the reactions of 5-nitro-3-thienylethyl chloride and acetate with the lithium salt of 2-nitropropane to give (83) (cf. this series, Vol. 2, p. 80) has been investigated. The cyano-group was not found to be sufficiently active, since 4-cyano-2-thienyl-methyl and -ethyl chlorides only gave O-alkylated products by an mechanism. The iSn(AEAE) reaction also occurred between benzenethiolate and 4-nitro-2-thienylmethyl acetate, and a moderate yield of 4-nitro-2-thienylmethyl phenyl sulphide was obtained. 

By Reduction of Carbonyl Compounds. Use of high (10 kbar) pressures has been shown to effect trialkylstannane reductions of ketones in the absence of radical initiators or Lewis acids.10 Zinc borohydride has been demonstrated to be a mild reducing agent for the conversion of benzenethiol esters into alcohols in good yield. Use of mixed solvents containing methanol has been found to confer some chemoselectivity upon reductions with lithium borohydride and permits enhanced rates of reduction of esters, lactones, and... 

Lithium, methyl-, 55, 7,10 Lithium, phenyl-, 55,11 Lithium phenylthio(alkyl)cupiates, 55,122 LITHIUM, phenyllhio(fert-butyl)cuprate [Lithium, phenylthio(l,l-dimethyl-ethyl)cuprate), 55,122 Lithium, 1-propenyl-, 55,111 LITHIUM, (E)-l-propenyl-, 55, 103 Lithium thiophenoxide [Benzenethiol, lithium salt], 55,122... 

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