chapter  11
20 Pages

Alkene and Alkyne Reactions with Cyclopalladated Organopalladium Complexes

WithRichard F. Heck, Guangzhong Wu, Weijing Tao, Arnold L. Rheingold

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.