The First Alkyl(silyl)palladium Complexes:  Formation by Oxidative Addition of Silacyclobutanes to Palladium Complexes, Reductive Elimination, and Other Reactivities Relevant to Catalysis

1,1-Diphenyl- and 1,1-dimethylsilacyclobutanes reacted with Me 2 Pd(dmpe) (dmpe = 1,2-bis(dimethylphosphino)ethane) or Pd(PhCH CH 2 )(dmpe) to give 2,2-diphenyl- and 2,2-dimethyl-1-pallada-2-silacyclopentane complexes, the diphenyl complex being characterized by X-ray analysis. Treatment of the diphenyl complex with acetylenes or 1,2-disilacyclopentane induced reductive elimination to regenerate the parent 1,1-diphenylsilacyclobutane. A dihydrosilane or a silacyclobutane reacted with the diphenyl complex to afford a 1,3-bis(hydrosilyl)propane or a 1,5-disilacyclooctane, respectively.