Palladium-Catalyzed Synthesis of Tetrasubstituted Olefins by Triple Domino Process

An efficient, highly regio- and stereo-selective protocol for the synthesis of tetrasubstituted olefins was developed to take place by a palladium(0)-catalyzed triple domino process. It involves the formation of three new C-C bonds through double carbopalladation and C-H activation across 2-bromoaryl alkynyl biaryls/heteroaryls with norbornene. This method is practically simple with broad substrate scope and tolerates a wide range of substituents. The products bearing 9H-pyrrolo[1,2-a] indole motifs reveal intriguing solid state fluorescence properties and thus form a new class of aggregation induced emission (AIE) fluorophores.