Alkene and Alkyne Reactions with Cyclopalladated Organopalladium Complexes
Cyclopalladated azobenzene tetrafluoroborate catalyzes the dimerization of styrene to 2,3-diphenyl-l-butene and the isomerization of allylbenzene. The complex reacts stoichiometrically with various disubstituted alkynes to form 2-phenylcinnolinium tetrafluoroborate derivatives, usually in good yields. Similar reactions occur with cyclopalladated N-substituted benzalimine salts, Disubstituted alkynes, for example, react to form N-substituted isoquinolinium salts. Other cyclopalladated complexes form naphthalene or pentasubstituted cyclopentadiene derivatives, 1,2,3,4-Tetraphenylnaphthalene derivatives have been obtained in modest yields catalytically from iodobenzene derivatives and diphenylacetylene. Vinylic bromides and diphenylacetylene with a palladium catalyst form fulvene derivatives in low yields.