- Diastereoselective Synthesis of Dialkylated Bis(phosphino)ferrocenes: Their Use in Promoting Silver-Mediated Nucleophilic Fluorination of Chloroquinolines
-
The diastereoselective synthesis of dialkylated ferrocenyl bis(phosphane)s bearing aryl, alkyl, and hetero- or polycyclic substituents on the phosphino groups is reported, together with their characterization in the solid state by X-ray structure analysis
- Roger, Julien,Royer, Sylviane,Cattey, Hélène,Savateev, Aleksandr,Smaliy, Radomyr V.,Kostyuk, Aleksandr N.,Hierso, Jean-Cyrille
-
-
Read Online
- Tetramethylammonium Fluoride Alcohol Adducts for SNAr Fluorination
-
Nucleophilic aromatic fluorination (SNAr) is among the most common methods for the formation of C(sp2)-F bonds. Despite many recent advances, a long-standing limitation of these transformations is the requirement for rigorously dry, aprotic conditions to maintain the nucleophilicity of fluoride and suppress the generation of side products. This report addresses this challenge by leveraging tetramethylammonium fluoride alcohol adducts (Me4NF·ROH) as fluoride sources for SNAr fluorination. Through systematic tuning of the alcohol substituent (R), tetramethylammonium fluoride tert-amyl alcohol (Me4NF·t-AmylOH) was identified as an inexpensive, practical, and bench-stable reagent for SNAr fluorination under mild and convenient conditions (80 °C in DMSO, without the requirement for drying of reagents or solvent). A substrate scope of more than 50 (hetero) aryl halides and nitroarene electrophiles is demonstrated.
- Bland, Douglas C.,Lee, So Jeong,Morales-Colón, Mariá T.,Sanford, Melanie S.,Scott, Peter J. H.,See, Yi Yang
-
supporting information
p. 4493 - 4498
(2021/06/28)
-
- PROCESS FOR FLUORINATING COMPOUNDS
-
Disclosed are mild temperature (e.g., from 0 to 80°C) SNAr fluorinations of a variety of halide and sulfonate substituted aryl and heteroaryl substrates using NMe4F.
- -
-
Page/Page column 29; 33; 34
(2017/02/28)
-
- Facile preparation of 3-substituted-2,6-difluoropyridines: Application to the synthesis of 2,3,6-trisubstituted pyridines
-
We report a facile method for the difluorination of 3-substituted-2,6-dichloropyridines using cesium fluoride as a fluorination reagent in dimethyl sulfoxide. It is proposed that this method for preparing 3-substituted-2,6-difluoropyridines is simpler and easier than those reported in previous literature. To examine the utility of 3-substituted-2,6-difluoropyridines in synthetic chemistry, we also demonstrate a subsequent conversion to 2,3,6-trisubstituted pyridines by a tandem nucleophilic aromatic substitution.
- Katoh, Taisuke,Tomata, Yoshihide,Tsukamoto, Tetsuya,Nakada, Yoshihisa
-
supporting information
p. 6043 - 6046
(2015/10/28)
-
- Acyl azolium fluorides for room temperature nucleophilic aromatic fluorination of chloro- and nitroarenes
-
The reaction of acid fluorides with N-heterocyclic carbenes (NHCs) produces anhydrous acyl azolium fluorides. With appropriate selection of acid fluoride and NHC, these salts can be used for the room temperature SNAr fluorination of a variety of aryl chlorides and nitroarenes.
- Ryan, Sarah J.,Schimler, Sydonie D.,Bland, Douglas C.,Sanford, Melanie S.
-
supporting information
p. 1866 - 1869
(2015/04/27)
-
- Anhydrous Tetramethylammonium Fluoride for Room-Temperature SNAr Fluorination
-
This paper describes the room-temperature SNAr fluorination of aryl halides and nitroarenes using anhydrous tetramethylammonium fluoride (NMe4F). This reagent effectively converts aryl-X (X = Cl, Br, I, NO2, OTf) to aryl-F under mild conditions (often room temperature). Substrates for this reaction include electron-deficient heteroaromatics (22 examples) and arenes (5 examples). The relative rates of the reactions vary with X as well as with the structure of the substrate. However, in general, substrates bearing X = NO2 or Br react fastest. In all cases examined, the yields of these reactions are comparable to or better than those obtained with CsF at elevated temperatures (i.e., more traditional halex fluorination conditions). The reactions also afford comparable yields on scales ranging from 100 mg to 10 g. A cost analysis is presented, which shows that fluorination with NMe4F is generally more cost-effective than fluorination with CsF.
- Schimler, Sydonie D.,Ryan, Sarah J.,Bland, Douglas C.,Anderson, John E.,Sanford, Melanie S.
-
p. 12137 - 12145
(2016/01/09)
-
- C-H FLUORINATION OF HETEROCYCLES WITH SILVER (II) FLUORIDE
-
The present invention provides compositions and methods for the selective C-H fluorination of nitrogen-containing heteroarenes with AgF2, which has previously been considered too reactive for practical, selective C-H fluorination. Fluorinated heteroarenes are prevalent in numerous pharmaceuticals, agrochemicals and materials. However, the reactions used to introduce fluorine into these molecules require pre-functionalized substrates or the use of F2 gas. The present invention provides a mild and general method for the C-H fluorination of nitrogen-containing heteroarene compounds to 2-fluoro-heteroarenes with commercially available AgF2. In various embodiments, these reactions occur at ambient temperature within one hour and occur with exclusive selectivity for fluorination at the 2-position. Exemplary reaction conditions are effective for fluorinating diazine heteroarenes to form a single fluorinated isomer.
- -
-
Paragraph 00123
(2015/02/19)
-
- Selective C-H fluorination of pyridines and diazines inspired by a classic amination reaction
-
Fluorinated heterocycles are prevalent in pharmaceuticals, agrochemicals, and materials. However, reactions that incorporate fluorine into heteroarenes are limited in scope and can be hazardous. We present a broadly applicable and safe method for the site-selective fluorination of a single carbon-hydrogen bond in pyridines and diazines using commercially available silver(II) fluoride. The reactions occur at ambient temperature within 1 hour with exclusive selectivity for fluorination adjacent to nitrogen. The mild conditions allow access to fluorinated derivatives of medicinally important compounds, as well as a range of 2-substituted pyridines prepared by subsequent nucleophilic displacement of fluoride. Mechanistic studies demonstrate that the pathway of a classic pyridine amination can be adapted for selective fluorination of a broad range of nitrogen heterocycles.
- Fier, Patrick S.,Hartwig, John F.
-
p. 956 - 960
(2013/12/04)
-
- CB1 MODULATOR COMPOUNDS
-
Novel compounds of structural formula (I) are disclosed. As modulators of the Cannabinoid-1 (CB1) receptor, these compounds are useful in the treatment, prevention and suppression of diseases mediated by the CB1 receptor. As such, compounds of the present invention are useful as in the treatment, prevention and suppression of psychosis, memory deficits, cognitive disorders, migraine, neuropathy, neuro-inflammatory disorders (e.g., multiple sclerosis, Guillain-Barre syndrome and the inflammatory sequelae of viral encephalitis), cerebral vascular accidents, head trauma, anxiety disorders, stress, epilepsy, Parkinson's disease, and schizophrenia. The compounds are also useful for the treatment of substance abuse disorders, particularly to opiates, alcohol, and nicotine. The compounds are also useful for the treatment of obesity or eating disorders associated with excessive food intake and complications associated therewith.
- -
-
Page/Page column 61
(2008/06/13)
-
- Amide derivative
-
A compound of the formula: wherein Ar is optionally substituted phenyl, etc.; n is 0, 1 or 2; R1is hydogen atom, optionally substituted alkyl, etc.; R2and R3are independently optionally substituted alkyl, etc.; R4and R5are independently hydrogen atom or optionally substituted alkyl; R6is hydrogen atom, hydroxy or alkyl; or a pharmaceutically acceptable salt thereof is useful as a medicament for treating retinal degenerative disorders and the like.
- -
-
-
- Carboxamidation of pyridines by the system of elemental fluorine- carbonitrile-water: A useful alternative to the chichibabin amination
-
The title reaction with pyridine, 4-methylpyridine, 3-methylpyridine, 3- bromopyridine, nicotinonitrile, and quinoline yields 2-carboxamido derivatives regioselectively. Isoquinoline is amidated at position 1.
- Kiselyov,Strekowski
-
p. 2387 - 2392
(2007/10/02)
-
- NUCLEOPHILIC FLUORINATION OF CHLORINATED N-HETEROCYCLES WITH TETRABUTYLPHOSPHONIUM HYDROGENDIFLUORIDE AND DIHYDROGENTRIFLUORIDE
-
Fluorination of various chlorinated N-heterocycles with tetrabutylphosphonium hydrogendifluoride (1) or dihydrogentrifluoride (2) readilly proceeded in high yields under mild conditions.
- Uchibori, Yukitaka,Umeno, Masayuki,Yoshioka, Hirosuke
-
p. 1507 - 1510
(2007/10/02)
-
- Preparation of 2-Fluoropyridines via Base-Induced Decomposition of N-Fluoropyridinium Salts
-
N-Fluoropyridinium salts with either BF4-, SbF6-, or PF6- as a counteranion were treated with excess base such as triethylamine at room temperature to give 2-fluoropyridine in good yield.This method was succesfully applied to the preparation of 2-fluoropyridine derivatives possessing electron-donating or -withdrawing substituents using substituted N-fluoropyridinium tetrafluoroborates.Pyridine-F2 compounds produced through reactions of pyridines with molecular fluorine were also treated with base to give 2-fluoropyridines but in low yields.These reactions are considered to occur through a carbene mechanism as follows: a novel N-F-containing cyclic carbene (3), generated from the N-fluoropyridinium salts by 2-proton abstraction, reacts with fluorine atoms from counteranions such as BF4-, SbF6-, or PF6-, followed by elimination of F- from the N-F moiety, to yield 2-fluoropyridines.Previously reported findings in reactions of pyridines with molecular fluorine are explained on the basis of this mechanism.
- Umemoto, Teruo,Tomizawa, Ginjiro
-
p. 1726 - 1731
(2007/10/02)
-