Sulfides alkynyl aryl

One of the classic routes to the synthesis of alkynyl aryl sulfides involved the treatment of bromoalkynes with sodium thiophenolate and related compounds [1(X)]. Using this approach, moderate to good yields of the alkynyl aryl sulfides were obtained under very mild conditions. Following this work, a considerable amount of effort has been focused on... 

SCHEME 5.66 Conversion of thiophenols into alkynyl aryl sulfides [103]. 

Bromination of the enol ether product with two equivalents of bromine followed by dehydrobromination afforded the Z-bromoenol ether (Eq. 79) which could be converted to the zinc reagent and cross-coupled with aryl halides [242]. Dehydrobromination in the presence of thiophenol followed by bromination/dehydrobromination affords an enol thioether [243]. Oxidation to the sulfone, followed by exposure to triethylamine in ether, resulted in dehydrobromination to the unstable alkynyl sulfone which could be trapped with dienes in situ. Alternatively, dehydrobromination of the sulfide in the presence of allylic alcohols results in the formation of allyl vinyl ethers which undergo Claisen rearrangements [244]. Further oxidation followed by sulfoxide elimination results in highly unsaturated trifluoromethyl ketonic products (Eq. 80). 

Elimination. Conjugated enynes and styrenes are formed from p-hydroxy sulfides that are derived from 2-alkynyl- and l-aryl-l,3-dithiolanes. The reaction is considered as... 

We prepared di(l-alkynyl)sulfides, (RC==C)2S, in excellent yields by adding sulfur dichloride at very low temperatures to solutions of alkynyllithiums in Et20 [7]. Grignard derivatives gave poor results. In Chap. V and VI the successful preparation of di(thienyl)sulfides, di(furyl)sulfide and a di(aryl)sulflde are described, using THF as a solvent. All these reactions are extremely rapid and must be carried out at — 80 °C or lower in order to prevent the attack of SC12 on the product. 

Furans are formed from a-propargyl ketones. Alkynyl benzyl sulfides cyclize to give 2-aryl-2,3-dihydrothiophenes. Deprotonation at the benzylic position initiates the cyclization. 

I alkynyl sulfides with cate-/cJ by NiChCdppe). t a /.lic and aryl C-O bonds" is rr> "-coupling of vinyl Grignard... 

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