Intramolecular Oxidative Palladium-Catalyzed Amination Involving Double C–H Functionalization of Unactivated Olefins
Intramolecular palladium-catalyzed amination reactions are becoming important tools for the synthesis of various nitrogen-containing­ heterocycles. This account highlights the developments achieved in this field by domino processes in oxidative conditions using unactivated olefins, due to their advantages in terms of step economy and efficiency. These reactions involve the change of oxidation state in the palladium intermediate, requiring the presence of an oxidizing agent to regenerate the catalytic cycle. This kind of additive is essential for the success of the reaction and it can also furnish nucleophilic species that are incorporated into the final product. Reactions can occur at either the intra/intra- or intra/intermolecular level, providing valuable methodologies for the preparation of (poly)heterocyclic scaffolds. Besides, procedures based on the use of strengthened catalytic systems, more recently, disclosed intriguing conditions have enlarged the possibility to modulate the substrate reactivity. Perspectives in this field are directed to the discovery of new reaction conditions, focusing on the employment of oxidatively stable ligands useful for the asymmetric catalysis­. 1 Introduction 2 Carboamination Reactions 2.1 Pd(0)/Pd(II) 2.2 Pd(II)/Pd(IV) 3 Aminooxygenation Reactions 3.1 Pd(0)/Pd(II) 3.2 Pd(II)/Pd(IV) 4 Diamination Reactions 4.1 Pd(0)/Pd(II) 4.2 Pd(II)/Pd(IV) 5 Aminohalogenation Reactions 5.1 Pd(0)/Pd(II) 5.2 Pd(II)/Pd(IV) 6 Conclusions