Reductive Coupling\nof N‑Heteroarenes and 1,2-Dicarbonyls\nfor Direct Access to γ‑Amino Acids, Esters, and Ketones\nUsing a Heterogeneous Single-Atom Iridium Catalyst

Despite their significant importance,\nthe challenges\nin direct\nand diverse synthesis of N-heterocyclic γ-amino acids/esters/ketones\nhamper exploration of their applications. Herein, by developing a\nmultifunctional heterogeneous iridium single-atom catalyst composed\nof silica-confined iridium species and a boron-doped ZrO<sub>2</sub> support (Ir-SAs@B-ZrO<sub>2</sub>/SiO<sub>2</sub>), we describe\nits utility in establishing a new reductive coupling reaction of N-heteroarenes\nand 1,2-dicarbonyls for selective and diverse construction of the\nas-described compounds in a straightforward manner. The striking features,\nincluding good substrate and functionality tolerance, high step and\natom economy, exceptional catalyst reusability, and diversified product\npost-transformations, highlight the practicality of the developed\nchemistry. Mechanistic studies reveal that the synergy between the\nactive Ir sites and acidic support favors a chemoselective reduction\nof the more inert N-heteroarenes and affords requisite enamine intermediates.\nIn this work, the concept on precise transformation of reductive intermediates\nwill open a door to further develop useful tandem reactions by rational\ncatalyst design.