Thioethers from alcohols

ETHERS, EPOXIDES AND THIOETHERS FROM ALCOHOLS AND THIOLS... 

SECTION 123 Ethers, Epoxides, and Thioethers from Alcohols and Thiols... 

Related Method Section 123 (Ethers, Epoxides and Thioethers from Alcohols and... 

Lithium salt p-toluenesulfonyl chloride Thioethers from alcohols... 

Preparation of 2 4-dinitrophenyl-sulphides. Dissolve about 0-5 g. (or 0 005 mol) of the mercaptan in 10-15 ml, of rectified spirit (or in the minimum volume necessary for solution warming is permissible) and add 2 ml. of 10 per cent, sodium hydroxide solution. Mix the resulting sodium mercaptide solution with a solution of 1 g. of 2 4-dinitrochlorobenzene in 5 ml. of rectified spirit. Reaction may occur immediately with precipitation of the thioether. In any case reflux the mixture for 10 minutes on a water bath in order to ensure the completeness of the reaction. Filter the hot solution rapidly allow the solution to cool when the sulphide will crystaUise out. RecrystaUise from alcohol. 

Boron trifluoride etherate (in HOAc, 60-80°, 15 min, high yields) also catalyzes formation of 5-diphenylmethyl and 5-triphenylmethyl thioethers from aralkyl alcohols. 

C). Also, the presence of a lithium alkoxide group allows the cyclization of primary as well as tertiary alkyllithiums at temperatures as low as — 78 °C. Thus, cyclopentanol derivatives 160 are easily obtained from alcohols 159 in very high yields and as single diastereoisomers (Scheme 45). As shown with thioether 161, when the alkoxide group is placed in a homoallylic position, the reaction is even more effective and cyclized product... 

Thioethers are said to be conveniently prepared from alcohols under mild conditions by reaction with sulphenimides such as (70) in the presence of tri-butylphosphine [equation (17)]. Both the succinimide and phosphine oxide by-... 

Sodium/alcohol Nucleophilic substitution with strong nucleophiles Thioethers from halides... 

Hydrocarbons from alcohols via bromides s. 18, 125 Replacement of hydroxyl by hydrogen via mesylates and iodides s. 19, 114 via mesylates and benzyl thioethers s. 16, 107 via ketones and cyclic mercaptals s. 16, 138 OH H... 

By performing the hydrolysis of thioesters in the presence of benzylic alcohols, transprotection of thiols could be successfully carried out in water. The reactions proceeded smoothly to give benzylic thioethers from thioesters in good yields (Scheme 3.35). 

Use of the methylsulphinyl carbanion as base is recommended for the synthesis of ethers from alcohols and alkyl halides. The catalysed formation of dimethyl ether from hydrogen and carbon dioxide has been reported. Carey has described the use of the silicon-modified organolithium reagent (73) in the preparation of vinyl thioethers (Scheme 151). In order to extend the scope of this reaction to include vinyl ethers themselves, an attempt was made to metalate trimethylsilylmethyl ether use of n-buty 1-lithium resulted in nucleophilic attack on silicon, whereas t-butyl-lithium abstracted the wrong proton, as shown in Scheme 151. 

Potassium hydroxide/alcohol Thioethers from thiolic acid esters s. 12, 688... 

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