Sodium alkyl thiolates, reaction with

In the presence of sodium hydroxide, thiols react with alkyl halides to form the sulfides (20) the reaction occurs via the sodium thiolate and is analogous to the well-known Williamson synthesis of ethers and can also be applied to obtain unsymmetrical sulfides (Scheme 18). Symmetrical sulfides may be prepared directly by condensation of sodium sulfide with alkyl halides (Scheme 18). These reactions are of the SN2 type, and consequently the optimum yields of sulfides are realised using primary alkyl halides. 

Several thiols occur naturally for example, skunk secretion contains 3-methyll-butanethiol and cut onions evolve 1-propanethiol, and the thiol group of the natural amino acid cysteine plays a vital role in the biochemistry of proteins and enzymes (see Introduction, p. 2). Primary and secondary thiols may be prepared from alkyl halides (RX) by reaction with excess sodium thiolate (SN2 nucleophilic substitution by HST) or via the Grignard reagent and reaction with sulfur. Tertiary thiols can be obtained in good yields by addition of hydrogen sulfide to a suitable alkene. Thiols can also be prepared by reduction of sulfonyl chlorides (Scheme l).la,2a... 

N-(a-Alkoxyalkyl)- and N-(a-[alkylthio]alkyl)amines. The high-yielding reactions with sodium alkoxides and sodium thiolates proceed at room temperature. 

Therefore, it is not necessary to prepare the thiolate in a separate reaction with a sttong base, as is required in the reaction of alcohols with sodium hydride. Sulfides are usually prepared by adding the alkyl halide to a basic alcoholic solution of the thiol. 

In 2010, Ueda and Hartwig reported on an iridium-catalyzed asymmetric allylation of sodium sulfinates 345 to branched allylic sulfones 348 with high regioselectivities and enantioselectivities (Scheme 46.40). Notably, the reaction proceeded with a broad range of acyclic allylic carbonates 346 and aryl and alkyl sodium sulfinates 345. Most recently, Zhao et al. developed the catalytic asymmetric allylic alkylations of acyclic allylic carbonates 346 using sodium thiophenoxide and alkyl thiolates 348 to give good-to-excellent selectivities for branched products 350 with excellent enantioselectivities. 

In the general context of donor/acceptor formulation, the carbonyl derivatives (especially ketones) are utilized as electron acceptors in a wide variety of reactions such as additions with Grignard reagents, alkyl metals, enolates (aldol condensation), hydroxide (Cannizzaro reaction), alkoxides (Meerwein-Pondorff-Verley reduction), thiolates, phenolates, etc. reduction to alcohols with lithium aluminum hydride, sodium borohydride, trialkyltin hydrides, etc. and cyloadditions with electron-rich olefins (Paterno-Buchi reaction), acetylenes, and dienes.46... 

Reaction of Resin-Bound Iron Complex (54) with Alkyl Mercaptans, Thiophenols, and Phenols (Fig. 9)31. Sodium thiolates are prepared analogously to the alkoxides from thiol and sodium hydride, except that dry DMF is used as a solvent. The substitution on the polymer-bound arene (54) is performed at 70° in DMF within 16 h. The resin is filtered and washed with DMF (2 x 50 ml), MeOH (2 x 50 ml), H20 (2 x 50 ml), MeOH (2 x 50 ml), and CH2CI2 (3 x 50 ml) and then dried in vacuo at 40° to yield a red resin. 

In a detailed study Johnston and his co-workers306 described the preparation of 6-(alkylthio)purines they were obtained by reaction either of 6-mercapto-purines with alkyl halides or of 6-chloropurine with sodium thiolates ... 

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 addition to well-known nucleophilic behavior of thiolate anions, sulfmates are also active in substitution reactions. To this end, the conversion of a primary alkyl iodide into an alkyl sulfone has been accomplished by simply stirring the sodium sulfinate salt with the alkyl halide in DMF at room temperature (Scheme 5.20) [21]. While only a few examples were described, this work demonstrates the ability of sulfinate salts to participate in nucleophilic substitution reactions. 

Sodium mercaptides are prepared from the mercaptans and aqueous or alcoholic solutions of sodium hydroxide or alcoholic sodium eth-oxide. The sodium mercaptide reacts with halides, chlorohydrins, esters of sulfonic acid, or alkyl sulfonates [6] to give sulfides in yields of 70% or more. A recent report describes a general procedure for synthesizing aryl thioesters by a nucleophilic displacement of aryl halide with thiolate ion in amide solvents. No copper catalysis is necessary as in an Ullmann-type reaction. 

Conditions have been worked out for the synthesis of methyl polyfluoroalkyl sulphides and 2-bromo-l,l-difluoroethyI phenyl sulphide by halogen-substitution reactions involving sodium thiolates. / -Nitrothiophenol reacts with 1,2-dichlorohexafluorocyclopentene to give the l,2-bis(p-nitrophenylthio)-analogue. Aryl alkyl tellurides PhTeR and bis(phenyltelluro)methane PhTeCHgTePh can be obtained from PhTeLi and an alkyl halide, or di-iodomethane, respectively. 

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