A Practical Synthesis of Biaryls and Aromatic Acetylenes by Stille Coupling in Room-Temperature Ionic Liquids

Abstract

The Stille cross-coupling reactions of aryl halides with aryl or alkynylstannanes have been achieved under mild conditions in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]), affording the corresponding biaryls and aromatic acetylenes in good yields. Use of this solvent allows for facile recycling of the solvent and catalyst system, which can be used at least five times without loss of activity.

GRAPHICAL ABSTRACT

Keywords:

• Alkynylstannane
• aromatic acetylene
• biaryl
• ionic liquid
• Stille coupling

ACKNOWLEDGMENTS

We thank the National Natural Science Foundation of China (20862008) and the Natural Science Foundation of Jiangxi Province of China (2008GQH0034) for financial support.

Notes

^a All reactions were performed using 1.0 mmol of aryl halide, 1.2 mmol of arylstannane, and 0.05 mmol of Pd(PPh₃)₄ in [Bmim][PF₆] (1.5 mL) at 80 °C under Ar.

^b Isolated yield based on aryl halide used.

^a All reactions were performed using 1.0 mmol of aryl halide, 1.2 mmol of alkynylstannane, and 0.05 mmol of Pd(PPh₃)₄ in [Bmim][PF₆] (1.5 mL) at 80 °C under Ar.

^b Isolated yield based on aryl halide used.