2693-66-5Relevant articles and documents
PARTIALLY FLUORINATED HETEROCYCLIC COMPOUNDS. PART 17 . THE PREPARATION OF FUSED 2H-PYRAN DERIVATIVES FROM POLYFLUOROARYL AND -HETEROARYL PROP-2-ENYL ETHERS WITH POTASSIUM FLUORIDE VIA AN ELECTROCYCLISATION REACTION. A NOVEL SIGMATROPIC PROTON SHIFT DURING THE REACTION OF...
Brooke, Gerald M.
, p. 483 - 492 (1983)
A new synthesis of fused 2H-pyran derivatives via an electrocyclisation reaction is described which is based on a novel route to o-quinomethide-type precursors.These transient materials are formed by the dehydrofluorination (with KF) in dipolar aprotic solvents of the Claisen rearrangement intermediates produced by the thermolyses of polyfluoroaryl and -heteroaryl prop-2-enyl ethers. 5,6,7,8-Tetrafluoro-2H-1-benzopyran (4) is formed from the C6F5-ether (1) in refluxing DMF while 5,6,7,8,9,10-hexafluoro-2H-naphthopyran (6) is obtained from the 2-naphthyl ether (5) in sulpholane at 155-162 deg.The 2,4,5,6-tetrafluoro-3-pyridyl ether (8) in sulpholane at 182 deg gave a mixture of 6,7,8-trifluoro-2H-pyranopyridine (10) (34percent) and 5,6,8-trifluoro-2H-pyranopyridine (12) (1percent), but 2,3,5,6-tetrafluoropyridyl ether underwent dealkylation to the 4-hydroxypyridine.The o-quinodimethide intermediate from pentafluorophenylprop-2-enyl sulphide (13) isimerised via a novel sigmatropic proton shift before cyclisation to 4,5,6,7-tetrafluoro-2-methylbenzothiophen (14).
Carboxylic Acid Deoxyfluorination and One-Pot Amide Bond Formation Using Pentafluoropyridine (PFP)
Brittain, William D. G.,Cobb, Steven L.
supporting information, p. 5793 - 5798 (2021/08/01)
This work describes the application of pentafluoropyridine (PFP), a cheap commercially available reagent, in the deoxyfluorination of carboxylic acids to acyl fluorides. The acyl fluorides can be formed from a range of acids under mild conditions. We also demonstrate that PFP can be utilized in a one-pot amide bond formation via in situ generation of acyl fluorides. This one-pot deoxyfluorination amide bond-forming reaction gives ready access to amides in yields of ≤94%.
The ionic liquid [bmim]Br as an alternative medium for the catalytic cleavage of aromatic C-F and C-Cl bonds
Prikhod'ko, Sergey A.,Adonin, Nicolay Yu.,Parmon, Valentin N.
scheme or table, p. 2265 - 2268 (2010/05/18)
The potential of [bmim]Br as an alternative to aprotic dipolar solvents in nickel-catalyzed hydrodehalogenation reactions is demonstrated. Hydrodechlorination of pentafluorochlorobenzene proceeds under the action of zinc in aqueous [bmim]Br. Under the above conditions aromatic C-F bonds also undergo slow cleavage. The reaction is significantly accelerated in the presence of nickel complexes with 2,2′-bipyridine or 1,10-phenanthroline. In the case of pentafluoroacetanilide highly regioselective ortho-hydrodefluorination leading to the formation of 3,4,5-trifluoroacetanilide is observed.
