402-44-8Relevant articles and documents
Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
supporting information, p. 15396 - 15405 (2021/10/12)
In ample variety of transformations, the presence of silver as an additive or co-catalyst is believed to be innocuous for the efficiency of the operating metal catalyst. Even though Ag additives are required often as coupling partners, oxidants or halide scavengers, its role as a catalytically competent species is widely neglected in cross-coupling reactions. Most likely, this is due to the erroneously assumed incapacity of Ag to undergo 2e? redox steps. Definite proof is herein provided for the required elementary steps to accomplish the oxidative trifluoromethylation of arenes through AgI/AgIII redox catalysis (i. e. CEL coupling), namely: i) easy AgI/AgIII 2e? oxidation mediated by air; ii) bpy/phen ligation to AgIII; iii) boron-to-AgIII aryl transfer; and iv) ulterior reductive elimination of benzotrifluorides from an [aryl-AgIII-CF3] fragment. More precisely, an ultimate entry and full characterization of organosilver(III) compounds [K]+[AgIII(CF3)4]? (K-1), [(bpy)AgIII(CF3)3] (2) and [(phen)AgIII(CF3)3] (3), is described. The utility of 3 in cross-coupling has been showcased unambiguously, and a large variety of arylboron compounds was trifluoromethylated via [AgIII(aryl)(CF3)3]? intermediates. This work breaks with old stereotypes and misconceptions regarding the inability of Ag to undergo cross-coupling by itself.
Oxidatively Induced Aryl-CF3 Coupling at Diphosphine Nickel Complexes
Bour, James R.,Roy, Pronay,Canty, Allan J.,Kampf, Jeff W.,Sanford, Melanie S.
supporting information, p. 3 - 7 (2020/01/03)
This communication describes the synthesis of a series of diphosphine NiII(Ph)(CF3) complexes and studies of their reactivity toward oxidatively induced Ph-CF3 bond-forming reductive elimination. Treatment of these complexes with the one-electron outer-sphere oxidant ferrocenium hexafluorophosphate (FcPF6) affords benzotrifluoride, but the yield varies dramatically as a function of diphosphine ligand. Diphosphines with bite angles of less than 92° afforded 3. In contrast, those with bite angles between 95 and 102° formed PhCF3 in yields ranging from 62 to 77%.
The Difluoromethylated Organogold(III) Complex cis-[Au(PCy3)(4-F-C6H4)(CF2H)(Cl)]: Preparation, Characterization, and Its C(sp2)-CF2H Reductive Elimination
Liu, Shuanshuan,Kang, Kai,Liu, Shihan,Wang, Decai,Wei, Ping,Lan, Yu,Shen, Qilong
, p. 3901 - 3908 (2018/10/25)
The preparation of the difluoromethylated organogold(III) complex cis-[Au(PCy3)(4-F-C6H4)(CF2H)(Cl)] (3) and its Ar-CF2H reductive elimination are described. In the presence of 1.0 equiv of AgSbF6 or AgPF6, compound 3 underwent a quantitative Ar-CF2H reductive elimination in less than 1.0 min at 25 °C, while the lack of silver salt resulted in Ar-CF2H reductive elimination from complex 3 in 1,1,2,2-tetrachloroethane (CCl2HCCl2H) after 80 min at 115 °C to afford the elimination product p-F-PhCF2H (4) and (Cy3P)Au(Cl) in quantitative yields. On the basis of the mechanistic studies of the kinetics of the reaction and DFT calculation, a concerted Ar-CF2H bond-forming pathway for the Ar-CF2H reductive elimination from organogold(III) complex 3 is proposed.
