Copper bis(2,2,6,6-Tetramethyl-3,5-heptanedionate)–Catalyzed Coupling of Sodium Azide with Aryl Iodides/Boronic Acids to Aryl Azides or Aryl Amines

Abstract

This work reports an efficient protocol for the coupling reaction of aryl iodides/boronic acids with sodium azide to aryl azides/amines in the presence of copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) Cu(TMHD)₂ catalyst. The Cu(TMHD)₂ catalyst is a structurally well-defined, O-containing, air- and moisture-stable, transition-metal complex and works at mild reaction conditions. It was observed that aryl azides can be reduced further to corresponding aniline derivatives using the same catalyst under basic reaction conditions for a prolonged period.

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GRAPHICAL ABSTRACT

Keywords:

• Amines
• aryl iodides
• azidation
• boronic acid
• copper

ACKNOWLEDGMENT

S. R. L. is thankful to the Department of Atomic Energy (ICT-DAE Centre), Mumbai, India, for a senior research fellowship.

Notes

^a Reaction conditions: iodobenzene (1 mmol), sodium azide (1.2 mmol), catalyst (0.25 mmol), ligand (0.50 mmol), solvent (4 ml), temperature (120 °C), reaction time (12 h); NR, no reaction.

^b GC yields.

^c KOH (3 mmol) product is aniline instead of azide.

^d Catalyst (0.20 mmol).

^e Catalyst (0.15 mmol).

^f Temperature (100 °C).

^g Temperature (90 °C).

^h Reaction time (5 h).

ⁱ Reaction time (6 h).

^a Reaction conditions: aryl iodide (1 mmol), sodium azide (1.2 mmol), catalyst (0.20 mmol), solvent (4 ml), temperature (100 °C), reaction time (6–12 h).

^b GC yields.

^c KOH (3 mmol).

^a Reaction conditions: aryl boronic acid (1 mmol), sodium azide (1.2 mmol), catalyst (0.20 mmol), solvent (4 ml), temperature (100 °C), reaction time (6–12 h).

^b GC yields.

^c KOH (3 mmol).