175676-42-3Relevant articles and documents
A Tunable Trifluoromethyliodonium Reagent
Liebing, Phil,Kalim, Jorna,Arefyeva, Natalia,Oehler, Florian,Wickleder, Mathias,Togni, Antonio
, p. 8585 - 8588 (2019)
Four complexes of MCl4 (M=Ti, Zr, Hf) with the hypervalent trifluoromethyl iodine reagent trifluoromethyl-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (1,=L) are described. With TiCl4, an I?O bond cleavage occurs, leading to the formation of the trifluoromethyliodonium alcoholate complexes [Ti2Cl6(L)4]Cl2 (2 a) and Ti2Cl8(L) (2 b). Reactions with ZrCl4 and HfCl4 form the complexes ZrCl4(L)2 (3) and HfCl4(L)2 (4), respectively, wherein the original I?O bond is retained and elongated compared to that in free 1. Therefore, the reactivity of 1 can be easily and practically fine-tuned by addition of different metal chlorides, following the order ZrCl4/HfCl444. Complexes 2 a, 3, and 4 are remarkably bench-stable forms of activated reagent 1, while 2 b is readily accessible in situ. 2 a and 2 b represent the first “real” trifluoromethyliodonium reagents derived from iodanes, that is, with the I?O bond being completely cleaved. The new complexes were shown to be useful for the trifluoromethylation of para-toluenesulfonate under aprotic conditions.
New hypervalent iodine reagents for electrophilic trifluoromethylation and their precursors: Synthesis, structure, and reactivity
Niedermann, Katrin,Welch, Jan M.,Koller, Raffael,Cvengro, Ján,Santschi, Nico,Battaglia, Philip,Togni, Antonio
experimental part, p. 5753 - 5761 (2010/09/18)
Several new five- and a six-membered heterocyclic monochloroiodanes, including two cationic species, were synthesized. Three of which were used for the preparation of corresponding trifluoromethylation reagents. These compounds were characterized by X-ray crystallography for a comparative structural study. A reactivity study on the trifluoromethylation of para-toluenesulfonic acid has been conducted in order to compare initial rates. Compounds having a longer I-O bond display a higher reactivity.
CF3 oxonium salts, O-(trifluoromethyl)dibenzofuranium salts: In situ synthesis, properties, and application as a real CF3+ species reagent
Umemoto, Teruo,Adachi, Kenji,Ishihara, Sumi
, p. 6905 - 6917 (2008/02/11)
(Chemical Equation Presented) We report in situ synthesis of the first CF3 oxonium salts, thermally unstable O-(trifluoromethyl)- dibenzofuranium salts, which furthermore have different counteranions (BF 4-, PF6-, SbF6 -, and Sb2F11-) and ring substituents (tert-butyl, F, and OCH3), by photochemical decomposition of the corresponding 2-(trifluoromethoxy)biphenylyl-2′- diazonium salts at -90 to -100°C. The yields markedly increased in the order of BF4- 6- 6- 2F11-. The CF3 oxonium salts were fully assigned by means of 1H and 19F NMR spectroscopy at low temperature. The CF3 salts decomposed to form CF4 and dibenzofurans. The half-life times at -60°C of the 2-tert-butyl salts having different counteranions were 29 min for BF4- salt 2d, 36 min for PF6- salt 2c, 270 min for SbF6- salt 2a, and 415 min for Sb2F11- salt 2b. Those at -60°C of the Sb2F11- salts having different 2-substituents were 13 min for F salt 3b, 63 min for H (unsubstituted) salt 1b, and 415 min for tert-butyl salt 2b. Thus, the stability of the CF3 oxonium salts increased in the order of BF4- 6 - 6- 2F 11- and F 3+ species source to the direct O- and N-trifluoromethylations of alcohols, phenols, amines, anilines, and pyridines under very mild conditions. The thermal decomposition method with a mixture of diazonium salt 17a and aryl- or alkylsulfonic acids, pyridine, or pyridines having an electron-withdrawing group also afforded CF3O or CF 3N products. The trifluoromethylation mechanism is discussed and an SN2 mechanism containing the transient formation of free CF 3+ is proposed. Thus, the present study has demonstrated that the exceedingly reactive CF3+ species can be generated much easier than the CH3+ species, contrary to the common sense that CF3+ is extremely difficult to generate in solution.
