Efficient Ligand-Free Copper-Catalyzed Arylation of Aliphatic Amines

Abstract

An efficient and practical protocol has been developed for the cross-coupling of alkyl amines and aryl iodides under ligand-free copper(I) iodide catalyzed conditions. A variety of alkyl amines undergo the catalytic system to afford the N-arylated products in moderate to good yields (up to 93%).

Key words

ligand-free - copper - aliphatic amines - N-arylation

References

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20

Representative Procedure for N-Arylation of Aliphatic Amines
A mixture of CuI (Sigma-Aldrich, 99.99% purity, 0.147 mmol), Cs₂CO₃ (2.94 mmol) was dissolved in (0.75 mL) DMF, the aryl halide (2.94 mmol), and the aliphatic amine (1.47 mmol) were added, and the mixture was stirred under air in a closed system at 135 ˚C for 24 h. The heterogeneous mixture was then cooled to r.t. and diluted with CH₂Cl₂. The resulting solution was directly filtered through a pad of Celite and the solvent removed under reduced pressure. The crude product was purified by silica gel column chromatography to afford the N-arylated product. The identity and purity of products was confirmed by ^¹H NMR and ^¹³C NMR spectroscopic analysis.