Palladium(0)-Catalyzed Amination, Stille Coupling, and Suzuki Coupling of Electron-Deficient Aryl Fluorides

Abstract

The amination of 2-fluoronitrobenzene was Pd(0) catalyzed at 65 degrees C in DMF, and the effectiveness of the catalysis was ligand-dependent. Among the five catalyst systems investigated, Pd(PPh3)4 was the most effective catalyst. The control experiments revealed that Pd(OAc)2 or PPh3 was not responsible for the catalysis. 4-Fluoro-3-nitro-benzonitrile and 4-fluoro-3-nitro-benzaldehyde also underwent Stille coupling and Suzuki coupling in the presence of Pd(PPh3)4, and the reactions afforded the coupling products in 28-86% yields. The control experiments showed no sign of reaction in the absence of palladium. These results were in agreement with the oxidative addition/reductive elimination pathway, where the oxidative addition could conceivably proceed via the SNAr mechanism.

Suzuki cross-coupling reaction of fluorobenzene with heterogeneous palladium catalysts

“…Specially good were the results obtained with K 2 CO 3 as the base (entry 3 in Table 1); in fact, conversion was close to 90% after 24 h of reaction. This is an excellent result as similar conversion levels can only be obtained with highly active homogeneous catalysts [7,8]. Rb 2 CO 3 also exhibited good conversion values, albeit somewhat lower than the previous ones.…”

“…The substrates most frequently used include aryl iodides, bromides and triflates; recently, however, aryl chlorides [3][4][5] have enabled great advances in this context by virtue of their being less expensive and readily available than the corresponding bromides and iodides. On the other hand, only a few, very recent references to Suzuki cross-coupling reactions involving aryl fluorides appear to exist [6][7][8].…”

Catalytic Transformations of Fluorinated Olefins

“…In fact, most of the reported Suzuki-Miyaura-type cross-coupling reactions via C-F bond cleavage have been conducted in the presence of a base [68][69][70][71][72][73][74][75][76][77][78][79]. Although this reaction leaves much to be desired regarding the catalyst loading as well as the product yield, it is of great importance in preparing substituted trifluorostyrenes bearing nitro, aldehyde, ester, and cyano groups.…”

Palladium Nanoparticles Supported on Polyaniline Nanofibers as a Semi‐Heterogeneous Catalyst in Water

“…In these cases, the reaction was considerably slower, requiring 24 h at 100 8C. Catalytic C À C cross-coupling reactions of fluoro derivatives are rare [31] because of the strong CÀF bond. Such reactions usually employ elaborate ligands to increase the reactivity of the catalytic center.…”