Derivatization Reactions with Aryllithium, Obtained by Br-Li Exchange

2 Derivatization Reactions with Aryllithium Obtained by Br—Li Exchange 

3 Reaction of Aryllithium with Carbon Disulfide and Subsequent Methylation [9] 

Whereas interaction between 2-thienyllithium and 2-furyllithium and carbon disulfide in THF affords the corresponding dithioates RCSSLi as the predominant products, aryllithium compounds seem to attack mainly on sulfur with formation of arenethiolates and tarry products [9]. If during the addition of carbon disulfide copper bromide is present in the solution, however, the desired formation of Ar—CSSLi does take place and subsequent addition of methyl iodide affords the dithioesters in good yields. Good results are also obtained when using less than stoichiometric amounts of CuBr. We therefore presume that carbon disulfide reacts more easily with the arylcopper intermediate than with aryllithium copper is subsequently transmitted from the copper dithioate to aryllithium. 

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