A method for generation of α-halo carbanions (carbenoids) from aryl α-haloalkyl sulfoxides with alkylmetals

Article abstract of DOI:10.1016/0040-4020(95)01078-5

Ligand exchange reaction of simple aryl α-haloalkyl sulfoxides with alkyllithium and ethylmagnesium halide at low temperature was investigated. On treatment of aryl α-haloalkyl sulfoxide with n-BuLi, t-BuLi, or EtMgX exclusively sulfur-alkyl bond-cleavage took place to afford α-halo carbanion (carbenoid). When this reaction was carried out without a proton source, the intermediate α-halo carbanion decomposed to give olefines in good yield. The ligand exchange reaction of sulfoxide was found to be very fast and the reaction could be carried out with a proton or a deuterium source (internal quench) to afford alkyl halide. This procedure offers a new method for preparing α-deuterated) halides (the halogen is F, Cl, or Br).