729-81-7Relevant 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.
Stille coupling involving bulky groups feasible with gold cocatalyst
Delpozo, Juan,Carrasco, Desiree,Perez-Temprano, Monica H.,Garcia-Melchor, Max,Alvarez, Rosana,Casares, Juan A.,Espinet, Pablo
supporting information, p. 2189 - 2193 (2013/04/10)
Gold shuttle: Bulky groups, which will not (or only very sluggishly) undergo Stille coupling with stannanes and inexpensive ligands, can be efficiently coupled using bimetallic catalysis. A gold cocatalyst serves as an efficient shuttle to convey the bulky group from tin to palladium by reducing the steric crowding in the transition-states (see scheme). Copyright
Facile cyclotrimerization of CF3C≡CH and CF3C≡CCF3 with bimetallic rhodium catalysts
Garcia, Juventino J.,Sierra, Carmen,Torrens, Hugo
, p. 6097 - 6098 (2007/10/03)
Complexes with the formation [{Rh(μ-SR(F)(C8H12)}2] (R(F) = C6F5 1, C6F4H-p 2 and C6H4F-p 3) have been used as catalyst precursors for the cyclotrimerization of CF3C≡CH and CF3C≡CCF3 at room temperature and under atmospheric pressure.
1-bromo-3,5-bis(trifhioromethyl)benzene: A versatile starting material for organometallic synthesis
Porwisiak, Jacek,Schlosser, Manfred
, p. 233 - 235 (2007/10/02)
1-Bromo-3,5-bis(trifluoromethyl)benzene (1) can be selectively prepared by treatment of 1,3-bis(fluorornethyl)benzene with N,N′-dibromo-5,5-dimethylhydantoin in strongly acidic media. A number of synthetically useful reactions via 3,5bis{trifluoromethyl)phenylmagnesium, -lithium, and -copper intermediates were accomplished. VCH Verlagsgesellschaft mbH, , 1996.
TRIFLUORMETHYLIERUNGSREAKTIONEN VON Te(CF3)2 MIT HALOGENBENZOLEN UND METHYLBENZOLEN
Naumann, Dieter,Kischkewitz, Jurgen
, p. 283 - 299 (2007/10/02)
Substituent effects on yields and regioselectivity of photochemical and thermal trifluoromethylation reactions of Te(CF3)2 with halogen benzenes and methyl benzenes are investigated under comparable conditions.All reactions lead to trifluoromethylated products.The yields of the thermal are always higher than those of the corresponding photochemical reactions.The reactivity of the halobenzenes increases in the series C6H5-F a sidereaction, but H-substitution is the primary reaction pathway.During the reactions with iodobenzene tellurium containing compounds are also formed.The reactions with methyl benzenes show an increase in reactivity in the series hexamethylbenzene mesitylene toluene p-xylene.In all cases only ring substituted products are detected.Reactions with toluene and p-xylene yield tellurium containing compounds as well as addition products.The 19F-n.m.r spectra of the products are given.
Der 2,4,6-Tris(trifluormethyl)phenylsubstituent; Beispiele fuer elektronisch und sterisch stabilisierte niederkoordinierte Hauptgruppenelemente
Scholz, Mario,Roesky, Herbert W.,Stalke, Dietmar,Keller, Klaus,Edelmann, Frank T.
, p. 73 - 86 (2007/10/02)
An improved synthesis of 1,3,5-tris(trifluoromethyl)benzene (1) is reported.RFPCl2 (3), RFPH2 (4) and the unusually stable diphosphene RFP=PRF (5) are readily accessible starting from Li (2) (=
Sodium Perfluoroalkane Carboxylates as Sources of Perfluoroalkyl Groups
Carr, Gillian E.,Chambers, Richard D.,Holmes, Thomas F.,Parker, David G.
, p. 921 - 926 (2007/10/02)
Sodium trifluoroacetate, in the presence of copper(I) iodide, is used as a source of trifluoromethyl to replace halogen by trifluoromethyl in benzenoid and heterocyclic aromatic systems, as well as in alkenyl and alkyl halogen compounds.The mechanism of this interesting copper-assisted process has been explored and an intermediate of the form - is proposed.Introduction of higher perfluoroalkyl groups from their respective sodium perfluoroalkane carboxylates has been demonstrated and the machanistic features are compared with those of the trifluoromethylation process.
POLYFLUOROARYL ORGANOMETALLIC COMPOUNDS. XVII. 2,4,6-TRIS(TRIFLUOROMETHYL)PHENYLLITHIUM, A STERICALLY CROWDED SYSTEM
Carr, G. E.,Chambers, R. D.,Holmes, T. F.,Parker, P. G.
, p. 13 - 24 (2007/10/02)
A lithium derivative (3) is generated from 1,3,5-tris(trifluoromethyl)benzene (2) and is shown to be remarkably stable.It is shown that 2 is less acidic than pentafluorobenzene, in competition for butyllithium.A preliminary survey of reactivity shows that
Thiirene formation in the reactions of sulfur atoms with alkynes
Verkoczy, Bela,Sherwood, Alden G.,Safarik, Imre,Strausz, Otto P.
, p. 2268 - 2281 (2007/10/02)
The gas phase reactions of S(1D2) and S(3PJ) atoms with alkynes have been studied by photolyzing COS in the presence of CHCH, CF3CCH, and CF3CCCF3.In the reactions with CHCH, CS2, benzene, and thiophene were formed; with CF3CCH, eight products found with disubstituted thiophenes and trisubstituted benzenes as the major products.In the case of CF3CCCF3, only perfluorotetramethylthiophene was detected at low conversion but at long photolysis several new products were observed.Many of the reaction products characterized here have not been reported before.The formation and distribution of the reaction products could be rationalized by an overall mechanism in which the formation of the highly reactive primary adducts, thiirene and thioformylmethylene, is followed by bimolecular reactions yielding the principal end products.The formation of minor products could be explained by secondary photoisomerizations, secondary photolysis, and by secondary decompositions and the secondary reactions of sulfur atoms with primary products.