POLYCYCLIC AROMATIC RING SYNTHESIS USING PALLADIUM CATALYZED C-H ACTIVATION AND ENAMINE-CATALYZED [3+2] CYCLOADDITION REACTIONS IN HETEROCYCLES SYNTHESIS

Abstract

Huge advances have been made in the field of palladium catalyzed C-H activation in the past decade. The application of palladium catalyzed C-H activation to form complex, multifunctional substrates, especially directly C-H alkynylation are positively exploring. We have recently successfully elucidated a series of palladium catalyzed C-H alkynylation from commercial available material. These transformations included synthesis of highly substituted cyclopentadiene fused chromones from cascade reactions of coumarins with alkynes and C¿H/N¿H dual activation to synthesize benzazepines from isatin and alkynes; Recent years have witnessed an explosive growth in the field of iminium and enamine catalysis. Primary and secondary amines as catalysis in the cycloaddition transformation of biological and pharmaceutical compounds via the iminmium activation model have been greatly explored. We have successfully explored a series of enamine catalyzed [3+2] cycloaddition. These pioneering works consisted by enamine-promoted inverse-electron-demand [3+2] cycloaddition-from diazocarbonyls to pyrazoles and enamine-catalyzed [3+2] cycloaddition to assemble highly substituted 1,2,3-triazoles from phenyl azides and ketones.