269410-06-2Relevant 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.
Palladium(I) Dimer Enabled Extremely Rapid and Chemoselective Alkylation of Aryl Bromides over Triflates and Chlorides in Air
Kalvet, Indrek,Sperger, Theresa,Scattolin, Thomas,Magnin, Guillaume,Schoenebeck, Franziska
supporting information, p. 7078 - 7082 (2017/06/13)
Disclosed herein is the first general chemo- and site-selective alkylation of C?Br bonds in the presence of COTf, C?Cl and other potentially reactive functional groups, using the air-, moisture-, and thermally stable dinuclear PdI catalyst, [Pd(μ-I)PtBu3]2. The bromo-selectivity is independent of the substrate and the relative positioning of the competing reaction sites, and as such fully predictable. Primary and secondary alkyl chains were introduced with extremely high speed (5 min reaction time) at room temperature and under open-flask reaction conditions.
Lewis Acid–Base Interaction-Controlled ortho-Selective C?H Borylation of Aryl Sulfides
Li, Hong Liang,Kuninobu, Yoichiro,Kanai, Motomu
supporting information, p. 1495 - 1499 (2017/02/05)
An iridium/bipyridine-catalyzed ortho-selective C?H borylation of aryl sulfides was developed. High ortho-selectivity was achieved by a Lewis acid–base interaction between a boryl group of the ligand and a sulfur atom of the substrate. This is the first example of a catalytic and regioselective C?H transformation controlled by a Lewis acid–base interaction between a ligand and a substrate. The C?H borylation reaction could be conducted on a gram scale, and with a bioactive molecule as a substrate, demonstrating its applicability to late-stage regioselective C?H borylation. A bioactive molecule was synthesized from an ortho-borylated product by converting the boryl and methylthio groups of the product.
