Functionalization of Fluorinated Molecules by Transition-Metal-Mediated C–F Bond Activation To Access Fluorinated Building Blocks

Synthesis of polyfluorinated terphenyl and styrene derivatives by palladium catalysed CF bond activation of polyfluoronitroaromatic substrates

“…Coupling of pentafluoronitrobenzene 1a with one equivalent of an aryl boronic acid derivative 2 catalysed by Pd(PPh 3 ) 4 and KF in DMF at 80 o C gives the corresponding biphenyl product arising from substitution of the fluorine atom ortho to the activating nitro group as we described previously [5]. Analogous reaction of 1 with 2.2 equivalents gave the terphenyl systems 3 as the only fluoroaromatic products (Table 1).…”

“…However, recently a range of carbon-fluorine activation reactions catalysed 2 by a variety of transition metal catalysts (Pd, Rh, Ni, etc) have been reported to allow, for example, Stille, [1] Suzuki-Miyaura, [2] and borylation [3] processes for highly fluorinated aromatic substrates and the field has now been very comprehensively reviewed recently by Braun and coworkers. [4] Previously, we demonstrated that highly fluorinated nitrobenzene derivatives could be used as substrates for C-F activation processes activated by inexpensive, commercially available Pd(PPh 3 ) 4 catalyst for the synthesis of various biphenyl [5] and aryl-alkynyl [6] derivatives by sp 2 -sp 2 and sp 2 -sp Suzuki-Miyaura type cross coupling processes respectively. In this paper, we present the synthesis of some terphenyl and styrene systems by Pd catalysed C-F activation processes involving polyfluorinated nitrobenzene precursors, further extending the use of transition metal catalysed carbon-fluorine bond activation processes.…”

“…In this paper, we present the synthesis of some terphenyl and styrene systems by Pd catalysed C-F activation processes involving polyfluorinated nitrobenzene precursors, further extending the use of transition metal catalysed carbon-fluorine bond activation processes. The use of various nickel and palladium catalysts for the cross coupling of highly fluorinated heteroaromatic systems, such as pentafluoro-and 2,3,5,6-tetrafluoro-pyridine, with vinyl-tin based reagents by Stille processes were discussed by Braun [1b,4] but no analogous processes using vinyl boron derivatives have been reported for the synthesis of polyfluorinated styrene systems.…”

Activation and Formation of Aromatic C–F Bonds

“…The activation of aryl C-F bonds is a long-standing challenge, owing to the strength of the C-F bond [46][47][48]. Such a process is also relevant to the development of methods to synthesize functionalized aryl fluorides.…”

Aromatic C–F Bond Activation by Rare-Earth-Metal Complexes

“…3 Despite the difficulty associated with C-F bond activation, metal mediated C-F bond transformations have been demonstrated and reviewed in the literature, including examples for both early and late transition metals. [15][16][17][18][19][20][21][22] Albeit in most cases C-F bond activation was achieved in a stoichiometric fashion due to the high stability of the corresponding metal fluoride, a common product of metal mediated C-F bond transformations, it is possible to make the reaction catalytic through the use of a fluorine trapper such as a silane or aluminum hydride by taking advantage of the strength of the Si-F and Al-F bonds. [23][24][25][26][27] Scheme 1.…”