Rhodium-Catalyzed Dimerization of Diaryl Acetylenes in the Presence of Grignard Reagents: Synthesis of 1,2,3-Triphenyl Naphthalene Derivatives

Abstract

An efficient Rh-catalyzed dimerization of diaryl acetylenes was achieved in the presence of Wilkinson catalyst, AgF₂, and 1.5 equivalent of PhMgBr in toluene, providing the 1,2,3-triaryl naphthalene derivatives in moderate to good yields.

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GRAPHICAL ABSTRACT

Keywords:

• Diaryl acetylenes
• dimerization
• Grignard reagents
• rhodium-catalyzed
• 1,2,3-triaryl naphthalene

ACKNOWLEDGMENTS

We thank the Key Project of Chinese Ministry of Education (No. 209054) and Major Technology Program of Zhejiang Province (2008C11062-1) for financial support.

Notes

^a All reactions were run with diphenyl acetylene (0.2 mmol), PhMgBr (0.6 mL of 0.5 M in THF, 0.3 mmol) or additive (0.3 mmol), catalyst (5 mol %), and oxidant (0.2 mmol) in dry toluene (3 mL) under N₂, 110 °C, 12 h.

^b Isolated yield.

^a Reaction conditions: diaryl acetylene (0.2 mmol), PhMgBr (0.6 mL of 0.5 M in THF, 0.3 mmol),Rh(PPh₃)₃Cl (5 mol%), and AgF₂ (0.2 mmol) in dry toluene (3 mL) under N₂, 110 °C, 12 h.

^b Isolated yield.

^c 4-TolMgBr (0.4 mL of 1.0 M in THF) was employed.

^d The rations of the two isomers (in parentheses) were determined by ¹H NMR.