A system combining the tetraphosphine cis,cis, cis-1,2,3,4-tetrakis((diphenylphosphino)methyl)cyclopentane (Tedicyp) and [Pd(C 3 H 5 )Cl] 2 was found to promote the direct arylation of furans Via C-H functionalization in good yields using Very low catalyst loadings.The coupling reaction of furan derivatives with aryl halides provides an efficient method for the preparation of arylfurans. The classical method to perform this reaction is to employ an aryl halide with an organometallic derivative of furan (metal ) ZnX, 1 SnR 3 2 B(OR) 2 3 ) using a palladium catalyst (Scheme 1). However, these reactions require preparation of the furan organometallic derivative and provide either an organometallic or a salt (MX) as a byproduct.In the last few years, very interesting results for the coupling of aryl halides with aryl derivatives via C-H activation have been reported: for example, Fagnou has used simple palladium salts or Pd associated with monodentate ligands. 4 The direct coupling of furans with aryl halides via C-H activation/ functionalization of furans at low catalyst loadings would provide an economically and environmentally attractive procedure for the preparation of such compounds. A few results have already been reported for this coupling. To our knowledge, the first coupling of furans with aryl halides via C-H activation was described by Ohta et al. using tetrakis(triphenylphosphine)-palladium (5 mol %) and potassium acetate as base. 5a However, in general low to moderate yields of arylated products (0-60%) were obtained using this catalyst. This procedure was applied in a few syntheses of furan derivatives to give the arylated or biarylated furans in 13-73% yields. 5b,d,e The sterically hindered and electron-rich phosphine P(Cy) 3 (10 mol %) associated to PdCl 2 (5 mol %) also catalyzes the coupling of 2-furaldehyde with a variety of aryl iodides in good yields. 5c Finally, the coupling of 2-furaldehyde with bromobenzene using 10 mol % of Pd(OH) 2 /C as catalyst gave the coupling product in 75% yield. 5f Although monophosphine ligands have been successfully used for the coupling of furan derivatives with aryl halides via C-H activation, to the best of our knowledge, the efficiency of polydentate ligands for such couplings has not been demonstrated. Moreover, all of the reactions employing monophosphines as ligands were performed using high catalyst loadings (5-10 mol %). Therefore, an effective and selective method allowing high substrate/catalyst ratios for the coupling of these challenging substrates is still subject to significant improvement.The nature of phosphine ligands on complexes has an important influence on the rate of catalyzed reactions. In order to find more efficient palladium catalysts, we have prepared the tetrapodal phosphine ligand cis,cis,cis-1,2,3,4-tetrakis-((diphenylphosphino)methyl)cyclopentane (Tedicyp; Scheme 2), 6 in which the four diphenylphosphino groups are stereospecifically bound to the same face of the cyclopentane ring. A very high efficiency has been observed for Suz...