The reaction of organotin halides with zinc. The occurrence of 1,2-intermetallic shifts

Abstract

The reaction of organotin halides with zinc proceeds via the initial formation of reactive organotin-zinc compounds. The nature of the final reaction products depends on the reaction conditions. In aprotic solvents, in the absence of strongly coordinating ligands, tetraorganotin compounds are formed via alkylation or arylation by intermediate organozinc compounds. The latter are produced by 1,2-intermetallic shifts of organic groups in the initial organotin-zinc reaction product, and from redistribution and transmetallation reactions. In the presence of proton donors, the organozinc intermediates are protolysed to the corresponding hydrocarbons. Strongly coordinating ligands prevent the 1,2-shifts, and hexaalkyl- or hexaarylditin compounds are formed. The unexpected formation of tetramethyltin form the reaction of mixed methylphenyl-tin monochlorides with zinc appears to involve a redistribution reaction between tetraorganotin compounds and zinc chloride. The reactions of diphenyltin dichloride and phenyltin trichloride with zinc give triphenyltin chloride, again via initially-formed organotin-zinc compounds.