Palladium-Catalyzed Hydrometalation and Bismetalation of Biphenylene

2-Silyl- and 2-borylbiphenyls have been synthesized by the palladium-catalyzed reaction of biphenylene with hydrosilanes and a hydroborane, respectively, via the cleavage of the four-membered ring of biphenylene. Under similar conditions, the C-C bond of biphenylene undergoes formal sigma-bond metathesis with various intermetallic linkages to afford 2,2'-bis(metallo)biphenyls.