Copper-pyrimidine bonds

Based on the previously described silver complex [Au2Ag2(Q)f,s)4(MeCN)2 , the same reaction with CuCl in acetonitrile but with addition of an equivalent of pyrimidine leads to the polymeric [CuAu(C6F5)2(MeCN)((J.2-C4H4N2)]n [66]. The polymerization of this complex is produced by covalent copper-pyrimidine bonds. The environment of the copper centers also comprises unsupported gold-copper interactions of 2.8216(6) A and one molecule of acetonitrile, leading to a distorted tetrahedral arrangement (see Figure 6.26). 

When the previous reaction is carried out in the same solvent (acetonitrile) with the addition of one equivalent of pyrimidine, the polymeric species [CuAu(C6F5)2(MeCN)(p,2-C4H4N2)] is obtained in high yield.45 In this case, the chain of metals is different from the previous case, and polymerization is produced by covalent copper-pyrimidine bonds with pairs of gold-copper interactions (2.8216(6) A). The environment of the copper centers is tetrahedral, with one acetonitrile molecule occupying the fourth position (Fig. 14). 

Representative reactions of pyrrolo[2,3-d]pyrimidine triflate 3436 using four major types of palladium-catalyzed carbon-carbon bond-forming reactions are illustrated in Eq. 6. Thus, methoxycarbonylation of 34 was performed using the standard protocol of Ortar and co-workers37a and afforded ester 35 in good yield. The Heck reaction with an electron-deficient alkene, represented by ethyl acrylate, provided 36 in respectable yield.37b The copper (I)-promoted coupling with A-trifluoro-... 

The copper-catalyzed decarboxylative coupling of a-keto carboxylic acids with indoles can proceed through C-H bond cleavage at their C3-position (Scheme 4.76) [78]. In contrast, the coupling with Ar-(pyrimidin-2-yl)indoles occurs at their C2-position under palladium catalysis [79]. 

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