A Highly Reactive Rhodium(I)–Boryl Complex as a Useful Tool for CH Bond Activation and Catalytic CF Bond Borylation

Nickel fluoro complexes as intermediates in catalytic cross-coupling reactions

“…Note that for the C-F activation step several mechanism have been discussed [3,6,26]. A phosphine-assisted mechanism has been suggested, and comparable reaction pathways were found at rhodium, iridium and platinum [16,19,60,61]. However, Johnson et al suggested a concerted oxidative addition for the activation of 2,3,5,6-tetrafluoropyridine at [Ni(h 2 -C 14 H 10 )(PEt 3 ) 2 ] [62].…”

“…In addition the formation of second product was observed which we tentatively assign as Cs[(4-OC 5 NF 4 )]. The same compound was formed in an NMR experiment in a reaction of Cs 2 CO 3 with pentafluoropyridine at 60 8C and was identified by its 19 F NMR spectroscopic data : À102.6 (m, 2F), À172.0 (m, 2F)] and its mass spectrum.…”

“…The structure which is proposed for 1 is supported by the 31 P{ 1 H}, 19 [6,23,27,28,[52][53][54][55][56][57]. The assignment of 1 as a 2-tetrafluoropyridyl nickel derivative is based on the presence of four signals of equal integration at d À86.0, À130.6, À151.8 and À174.0 in the 19 F NMR spectrum.…”

Catalytic Transformations of Fluorinated Olefins

“…The turnover number in this reaction reached as high as 250. Stoichiometric treatment of a rhodium(I) boryl complex, (PEt 3 ) 3 Rh(Bpin), with hexafluoropropylene results in the formation of a Z-perfluoropropenyl rhodium(I) species and its isomer, (CF 2 ¼C(CF 3 ))Rh(PEt 3 ) 3 , in a ratio of 2:7, which indicates that the Rh(I)-boryl complex might be a reaction intermediate in the catalytic transformation of hexafluoropropylene and HBpin into Bpin-derivatized trifluoropropanes [39]. Saeki and Tamao have demonstrated that (dppp)PdCl 2 (dppp ¼ 1,3-bis(diphenylphosphino)propane) is effective for the cross-coupling reaction of 1-(2,2-difluorovinyl)naphthalene with ( p-tol)ZnCl, leading to the selective formation of (Z )-fluoroalkene as a major product (Scheme 19) [53].…”

Activation and Formation of Aromatic C–F Bonds

“…46) [92]. DFT studies indicated that the observed regioselectivity originated through a boryl-assisted pathway.…”