Alkali metal thiolates

Esters of thioarsenious acid, As(SR)3 (R = Me, Et, Pr , Bu", Bu Ph), may be obtained by reacting alkali metal thiolates with arsenic halides (equation 9). In difficult cases (steric hindrance) more vigorous methods are used, e.g. (Bu S)3As (equation 10). 

Alkylmercaptomethyleneiminium salts as well as alkoxymethyleneiminium salts are transformed to amide thioacetals (443 equation 206) by alkali metal thiolates and thiols. - The action of alcoholic alkoxides on 2-alkoxy-2-dialkylaminocarbonitriles (444 equation 207) produces amide acetalsJ Spi-locyclic amide acetals (446 Scheme 82) were prepared from oxazolium salts (445) and substituted sal-icyl aldehydes. The addition of alcohols to the l,3-oxazolium-4-olate (447) affords heterocyclic amide acetals (448). ... 

Within this context, the present article concentrates on transition metal cluster complexes of cobalt, iron and manganese with mixed chalcogen/carbonyl ligand spheres obtained by reaction of simple binary metal carbonyls with alkali-metal sulfides, alkali-metal thiolates or transition-metal thiolate complexes and their selenium or tellurium counterparts. 

Several approaches have been used to prepare transition-metal-thiolate complexes. The most common synthetic route involves the metathesis reaction of a metal halide with an alkali metal thiolate salt. For instance, [(DPPE)Pd(Ar)(S-t-Bu)] was obtained by treatment of the (DPPE) palladium aryl iodide complex with sodium fprf-butyl thiolate (Equaticm 4.106). Additionally, these compoimds have been formed by proton exchange reactions of thiols with M-C (Equation 4.107), ° M-W and M-O, bonds (Equation 4.108). Finally, the oxidative addition of RSH, or alkyl and aryl disulfides - is a useful way... 

In 1979, the reaction of styrenyl and hexenyl halides with an alkali metal thiophenolate and ethanethiolate was reported (Equation (40))130 Reaction yields exceeded 90%, and the products retained the geometry of the starting olefin. In contrast to the stereospecificity of palladium-catalyzed couplings involving vinyl halides, nickel-catalyzed couplings of vinyl halides with thiolates gave mixtures of stereoisomeric products 131... 

Benzenedithiols are traditionally prepared by reductive dealkylation of 1,2-C6R4(SR )2, which in turn are obtained by treatment of dibromobenzenes with alkali metal or cuprous thiolates. The methodology continues to be used, for example, for crown ether-appended derivatives (15). A newer and more powerful synthesis of 1,2-benzenedithiol and its derivatives has been developed (16). This method (17) involves reaction of the benzenethiol with 2 equiv of BuLi to give 2-LiC6H4(SLi), which reacts with elemental sulfur to give the dithiolate (Eq. 1). 

Vogtle and Meurer explained the favoured formation of strain ring compounds in the synthesis of cyclophanes by cyclizations with cesium thiolates by a preorientation (preorganization) of the reactants at the cesium cation [82], For the cesium ion in contrast to the smaller alkali metal cations the capabiUty of forming an 11-membered intermediate is ascribed, which would favour an intramolecular course of the reaction (Fig. 4). 

Thiols are more acidic than the corresponding alcohols and are converted into their salts using alkali metal hydroxides or alkoxides. The thiolate salts are powerful nucleophiles, a property which has been used in the cleavage of methyl esters and methyl ethers. The combination of a hard acid and a soft base such as lithium propanethiolate (Li SPr) may favour attack on the methyl group of an ester and lead to alkyl-oxygen fission of the ester, rather than the more common addition of a nucleophile to the carbonyl group and consequently acyl-oxygen fission. This is particularly useful in the hydrolysis of hindered esters. 

Srj I reactions can be initiated by photochemical excitation, electrochemical reduction, and solvated electrons (alkali metal in ammonia). In some cases, spontaneous thermal initiation can also take place. The leaving group, X , is often a halide—frequently bromide or iodide, never fluoride. The nucleophile, Y , is commonly a nitroalkane anion (5-25) or another anion such as thiolate (RS ), phenolate (PhO ), or various enolates. 

Anionic polymerization of thietane and various 2-, 3- and polysubstituted thietanes has been achieved with alkali metals (Li, Na, K, Cs, Rb), naphthyl sodiumn-butyllithium, °" 1,4-dilithio-l, 1,4,4-tetraphenylbutane, and a thiolate anion.Treatment of 3-chlorothietane with aqueous sodium thiocyanate is said to give polymeric material.Polymerization of thietane has been effected with Grignard reagents.Thietane and substituted thietanes have been polymerized with dialkyl zinc reagents.A copolymer has been obtained by treating 2-methylthietane and styrene with -butyllithium a block copolymer has been derived from thietane and isoprene. " Copolymers of thietane and 3,3-dimethylthietane with pivalolactone have been reported. ... 

The reaction of alkali metal salts of a,/1-ethylene thiolates with 4-methyl-... 

In the anionic polymerization the situation is different. The negative charges are highly concentrated at the chain end at least for alcoholate and thiolate anions, alkali metal cations usually used as counterions have... 

Saturated perfluorocarbons are not only thermally stable, but also, in general, chemically unreactive. However, they undergo facile defluorination on reaction with strong reducing agents such as alkali metals and benzene thiolates, which are employed for etching perfluo-ropolymers [17]. 

Treatment of the < -arylhydrazono-3-thiazoline-2-acetic acid derivatives (141 R=H,Me,Et,6Bu,R1=H,Me,Ar=Ph,2,4,6-MegCgH2) with an alkali metal hydroxide (Lil/pyridine/DMF or lithiumpropane thiolate) effects rearrangement to the 2-aryl-6-thia-2,3,8-triazabicyclof3.2.1]-oct-3-en-4-carboxylates(142). An X-ray crystal structure showed the product (R=Me,R1=H,Ar=Ph) to exist as (142) in the solid. However, in solution an equilibrium between (142) and (143) occurs. Alkylation and acylation occur only through (143)1". A large number of mono-,di-,tri-,or tetraalkyl-A -thiazolines have been synthesised... 

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