Synlett 2004(5): 0877-0879  
DOI: 10.1055/s-2004-817783
LETTER
© Georg Thieme Verlag Stuttgart · New York

Novel and Efficient Synthesis of Symmetrical Functionalized Biaryls Using Zinc and Triethylammonium Formate

K. Abiraj, G. R. Srinivasa, D. Channe Gowda*
Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore, Karnataka, 570 006, India
Fax: +91(821)2421263; Fax: +91(821)2518835; e-Mail: dcgowda@yahoo.com;
Further Information

Publication History

Received 6 October 2003
Publication Date:
24 February 2004 (online)

Abstract

Reductive homocoupling of aryl halides in the presence of commercial zinc dust and triethylammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. The reductive coupling did not occur without triethylammonium formate. Addition of one equivalent of sodium hydroxide enhanced the coupling reaction rate. The commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).

17

For zinc/nickel catalyst-promoted reaction, reductive elimination of Ar2Ni affording Ar2 was proposed as a plausible mechanism. [11]

18

The spectra were compared to those of a commercial sample.