Copper (I) halides catalyse the formation of carbodithioates RCSSLi in the reaction of aryl-or heteroaryl-lithium reagents with carbon disulfide. Subsequent addition of methyl iodide gives the dithioesters RCSSCH3 in high yields. Appreciable amounts of the methyl sulfides RSCH3 and tars are obtained when the reaction with CS2 is carried out in the absence of copper (I) salts, especially in the case of more basic organoalkali compounds.
