Pd-catalyzed alkyl to aryl migration and cyclization: an efficient synthesis of fused polycycles via multiple C-H activation

We have previously reported that intramolecular C-H activationin organopalladium intermediates derived from o-halobiaryls leadsto a 1,4-palladium aryl to aryl migration and shown that suchintermediates can be trapped by Heck reactions and intramoleculararylation.Herein, we wish to report 1,4-palladium alkyl to arylmigrations via through-space C-H activation, followed by intramoleculararylation or an intermolecular Heck reaction, whichprovide a very efficient way to synthesize fused ring systems.