28293-53-0

Upstream product

• 652-31-3 2,3,4,5,6-pentafluorobenzamide 
• 2251-50-5 pentafluorobenzoylchloride 
• 181183-63-1 2,3,5,6-C₆F₄HCCl₃ 
• 5216-17-1 2,3,5,6-tetrafluorobenzonitrile 

Relevant academic research and scientific papers

Diazaphospholene-Catalyzed Hydrodefluorination of Polyfluoroarenes with Phenylsilane via Concerted Nucleophilic Aromatic Substitution

The metal-free catalytic C-F bond activation of polyfluoroarenes was achieved with diazaphospholene as the catalyst and phenylsilane as the terminal reductant. Density functional theory calculations suggested a concerted nucleophilic aromatic substitution mechanism.

Catalyst-Free Hydrodefluorination of Perfluoroarenes with NaBH4

Presented is an economical means of removing fluorine from various highly fluorinated arenes using NaBH4. The procedure was adapted for different classes of perfluoroarenes. A novel isomer of an emerging class of organic dyes based on the carbazole phthalonitrile motif was succinctly synthesized in two steps from tetrafluorophthalonitrile, demonstrating the utility of the hydrodefluorination procedure. Initial exploration of the dye shows it to be photoactive and capable of facilitating contrathermodynamic styrenoid E/Z isomerization.

Hydrodefluorination of functionalized fluoroaromatics with triethylphosphine: A theoretical and experimental study

Recently we reported the metal free hydrodefluorination of selected fluoroaromatics using triethylphosphine as the sole defluorinating agent. That prompted us to evaluate the mechanistic proposal and in the light of these results, along with new experimental evidence, we have now modified the initial proposal. The new mechanism avoids the highly energetic β-elimination step of roughly 71 kcal mol-1 for hexafluorobenzene and pentafluoropyridine at 393.15 K, invoking the participation of water. The use of D2O confirmed the role of water as the hydrogen source, yielding the corresponding deutero-defluorinated products; DFT calculations agree with this new proposed mechanism. We also report herein the use of this one-pot hydrodefluorination method applied to a broader number of fluoroaromatic derivatives; some of them allowed the collection of key mechanistic evidence.

Selective one-pot synthesis of aminopolyhalobenzonitriles from polyhalobenzotrichlorides in anhydrous ammonia

Polyhalogenated benzotrichlorides (pentafluoro-, chlorotetrafluoro-, chlorotrifluoro-, and tetrafluorobenzotrichlorides) undergo one-pot ammonolysis?+?aminodefluorination by the action of anhydrous ammonia to form mono- and diamino derivatives of polyhalobenzonitriles. For the substrates comprising halogen at the para-position, the ammonolysis of the CCl3 group and the first aminodefluorination occur simultaneously in the temperature range from ?33 to 5?°C. The temperature of introducing the second NH2 group is higher by 60–100?°C, whereby conditions were found for the selective synthesis of mono- and diaminopolyhalobenzonitriles. The use of anhydrous ammonia as a reagent and a solvent minimizes side reactions and simplifies an isolation of the high purity products.

Regioselective ortho-hydrodefluorination of pentafluorobenzoic acid by low-valent nickel complexes

2,3,4,5-Tetrafluorobenzoic and 3,4,5-trifluorobenzoic acids were prepared in high yields by reaction of C6F5COOH with zinc in the presence of NiCl2-2′-bipyridine (or 1,10-phenanthroline) complexes.

Reductive dehalogenation of polyfluoroarenes by zinc in aqueous ammonia

Aqueous ammonia has been found to be a good and versatile medium for the highly selective hydrodehalogenation of polyfluoroarenes by zinc under unprecedentedly mild conditions. The reduction of pentafluorobenzoic acid, 2,3,4,5,6-pentafluorobenzyl alcohol, pentafluorobenzamide, pentafluoropyridine, heptafluoro-2-naphthoic acid, 1,3,4,5,7,8-hexafluoro-2-naphthoic acid, octafluoronaphthalene, octafluorotoluene, decafluorobiphenyl, chloropentafluorobenzene and 4-chlorotetrafluorobenzoic acid give products derived from the removal of one or two halogen atoms. A reduction mechanism, proceeding through electron capture to give a radical anion and then fragmentation of the latter, has been suggested. The observed high selectivity of the process suggests a radical anion formed by direct electron transfer from zinc to substrate. The dehalogenation regioselectivity is basically in accordance with that expected for radical anion fragmentation.