摘要:
Alpha-Methylene-gamma-butyrolactone rings have been constructed by bis(benzonitrile)palladium dihalide or Pd-(OAc)2-LiX catalyzed cyclization reaction of haloallylic 2-alkynoates. A mechanism involving a trans halopalladation, followed by intramolecular insertion of a carbon-carbon double bond to a carbon-palladium bond and subsequent dehalopalladation, is briefly discussed.