Adaptive Photochemical\nAmination via Co(II) Catalysis

Transition-metal-catalyzed amination of aryl halides\nis one of\nthe most employed methods for constructing <i>N</i>-arylation\nadducts. However, the broad success of these reactions largely relies\non the screening of precatalysts, elaborated ligands, and case-by-case\noptimization of reaction conditions (solvent, base, additive, temperature, <i>etc.</i>) for electronically or structurally diverse nucleophiles.\nHerein, we report an adaptive photochemical C–N coupling of\naryl halides with various nitrogen nucleophiles (aliphatic and aromatic\namines, amides, sulfonamides, pyrazoles, and ammonium salts) by Co(II)\ncatalysis under the same reaction conditions (same precatalyst, same\nligand, same base, same solvent, same temperature) without the addition\nof any exogenous photocatalyst. This photochemical amination features\na wide substrate scope (>130 examples, up to 95% yield) with excellent\nfunctional group tolerance. Mechanistic studies indicate that these\nC–N coupling reactions may proceed via a Co(I)/Co(III) catalytic\ncycle.