Palladium-Catalyzed Synthesis of Carbo- and Heterocycles through Norbornene-Mediated ortho C-H Functionalization

Direct aromatic functionalization based on the use of a palladium catalyst and norbornene is a useful method to achieve straightforward synthesis of carbo- and heterocyclic compounds. New ring formation occurs through a cascade process triggered by ortho C–H alkylation (inter- and intramolecular) or arylation (homo­- and heterocoupling) of aryl iodides. Up to four new carbon–carbon bonds are generated under palladium control in a single operation. 1 Introduction 2 ortho C–H Alkylation 2.1 Intermolecular ortho C–H Alkylation 2.1.1 Heck Reaction 2.1.2 C–N Coupling 2.1.3 C–H Arylation 2.2 Intramolecular ortho C–H Alkylation 2.2.1 Heck Reaction 2.2.2 Cyanation Coupling 2.3 Coupling Inter- and Intramolecular ortho C–H Alkylation 3 ortho C–H Arylation 3.1 Homocoupling 3.2 Heterocoupling 3.2.1 α-Arylation/CO Addition 3.2.2 Heck Reaction 3.2.3 C–N Coupling 4 Conclusion