Synthesis, characterization and initial evaluation of 5-nitro-1-(trifluoromethyl)-3H-1λ³,2-benziodaoxol-3-one

Abstract

SummaryThe synthesis of 5-nitro-1-(trifluoromethyl)-3H-1λ3,2-benziodaoxol-3-one (3), a hypervalent-iodine-based electrophilic trifluoromethylating reagent, is described. Whereas considerations based on cyclic voltammetry and X-ray structural properties would predict an inferior reactivity when compared to the non-nitrated derivative 2, 19F NMR kinetic studies showed that this new derivative is almost one order of magnitude more reactive. Furthermore, differential scanning calorimetry measurements indicated that, in addition, it is also safer to handle.

Supramolecular Aggregation of Perfluoroorganyl Iodane Reagents in the Solid State and in Solution

“…The 19 F NMR signal is drastically downfield‐shifted compared with that of 4 ( δ = –40.1 ppm), and the shift is remarkably similar for both compounds { δ = –22.9 pm for [ 4 ‐H]NTf 2 and –22.6 ppm for [( 4 ) 2 H]BArF}. The downfield shift is typical for trifluoromethyl iodanes with enhanced iodonium character, as has been repeatedly reported , . Moreover, we noticed that the value of | 1 J C,F | is strongly influenced by protonation and decreases from 396 Hz for 4 in CDCl 3 to 371 and 372 Hz for [ 4 ‐H]NTf 2 and [( 4 ) 2 H]BArF, respectively.…”

“…The new derivatives 6 – 9 were characterized by 1 H, 13 C, and 19 F NMR spectroscopy as well as elemental analysis (C, H) and high‐resolution mass spectrometry. The crystalline H[SbF 6 ] adduct of acid reagent 1 , that is, [ 1 ‐H][SbF 6 ] · H 2 O, was accidentally obtained through the hydrolysis of NO[SbF 6 ] in a mixture with reagent 1 in CH 2 Cl 2 (Scheme a) . However, the water was important for crystallization, and this very reactive compound seems to be stabilized by hydrogen bonding.…”

“…A similar behavior was reported for an acid reagent related to 1 , which forms a crystalline 2:1 complex with Zn(OTf) 2 (OTf = trifluoromethanesulfonate) through the coordination of the exposed carbonyl oxygen atom , , . Moreover, several examples of the clean protonation of the acid and alcohol reagents with strong acids resulted in fairly stable iodonium salts , . For instance, 1 forms an adduct with 1 equiv.…”

“…For instance, 1 forms an adduct with 1 equiv. of H[SbF 6 ], [ 1 ‐H][SbF 6 ],, whereas the protonation of 4 with “Brookhart's acid” [H(OEt) 2 ]BArF {BArF = tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate} furnishes the mixed‐protonated salt [( 4 ) 2 H]BArF , . Both species were mentioned briefly in previous review articles, and we now provide their full characterization together with that of the new triflimide (NTf 2 ) salt [ 4 ‐H]NTf 2 …”

S‐Trifluoromethylation of Thiols by Hypervalent Iodine Reagents: A Joint Experimental and Computational Study

“…[1][2][3][4][5][6][7][8][9][10] Corresponding reagents for the trifluoromethylation of av ast array of substrates, as reported from our laboratory,f or example, 3,3-dimethyl-1-(trifluoromethyl)-1l 3 ,2-benziodoxol (1) [11][12][13][14][15][16] contributed to recent significant developments in organofluorine chemistry. [1][2][3][4][5][6][7][8][9][10] Corresponding reagents for the trifluoromethylation of av ast array of substrates, as reported from our laboratory,f or example, 3,3-dimethyl-1-(trifluoromethyl)-1l 3 ,2-benziodoxol (1) [11][12][13][14][15][16] contributed to recent significant developments in organofluorine chemistry.…”