651-83-2Relevant academic research and scientific papers
Palladium-Catalyzed C-H Silylation of Aliphatic Ketones Using an Aminooxyamide Auxiliary
Jiang, Chao,Li, Jianhua
, p. 5359 - 5362 (2021)
A palladium-catalyzed β-C(sp3)-H silylation of aliphatic ketones with disilanes to afford β-silyl ketones is reported. The aminooxyamide auxiliary is critical for the C-H activation and silylation. The reaction tolerates a number of functional groups and
Palladium-Catalyzed ortho-C(sp2)-H Silylation of Aromatic Ketones Using an Aminooxyamide Auxiliary
Li, Jianhua,Ding, Meiying,Jiang, Chao
supporting information, p. 9036 - 9040 (2021/11/24)
A palladium-catalyzed direct and selective ortho-C(sp2)-H silylation of aromatic ketones has been achieved using an aminooxyamide auxiliary. The reaction tolerates various orth-, meta-, and para- substituents on the aromatic ring and can be applied to thi
Hydrogen Bond Directed Photocatalytic Hydrodefluorination: Overcoming Electronic Control
Khaled, Mohammad B.,El Mokadem, Roukaya K.,Weaver, Jimmie D.
supporting information, p. 13092 - 13101 (2017/09/26)
The photocatalytic C-F functionalization of highly fluorinated arenes is a powerful method for accessing functionalized multifluorinated arenes. The decisive step in the determining regioselectivity in fluorine functionalization is fluoride fragmentation from the radical anion of the multifluorinated arene. To date, the availability of regioisomers has been dictated by the innate electronics of the fluorinated arene, limiting the synthetic utility of the chemistry. This study investigates the remarkable ability of a strategically located hydrogen bond to transcend the normal regioselectivity of the C-F functionalization event. A significant rate acceleration is additionally observed for hydrodefluorination of fluorines that can undergo intramolecular hydrogen bonds that form 5-8-membered cycles with moderately acidic N-H's. The hydrogen bond is expected to facilitate the fragmentation not only by bending the C-F bond of the radical anion out of planarity but also by increasing the exothermicity of the fluoride extrusion step through protonation of the naked fluoride. Finally, the synthetic utility of the method is demonstrated in an expedited synthesis of the trifluorinated α-phenyl acetic acid derivative required for the commercial synthesis of Januvia, an antidiabetic drug. This represents the first synthesis of a commercially important multifluorinated arene via a defluorination strategy and is significantly shorter than the current strategy.
General and efficient synthesis of polyfluorinated 2-aminotolans and 2-arylindoles
Politanskaya, Larisa V.,Shteingarts, Vitalij D.,Tretyakov, Evgeny V.
, p. 85 - 98 (2016/07/19)
It was established here that cross-coupling of polyfluorinated 2-iodoanilines with arylacetylenes in MeCN in the presence catalytic amounts of Pd(PPh3)2Cl2, CuI and Et3N produces the corresponding 2-aminotolans although their yields are decreased from 98% to 40% with increasing fluorination of the substrates. It was shown that the 2-aminotolans with six or fewer fluorine atoms in their rings can be heterocyclised by heating in ethanol containing p-TSA to produce the corresponding polyfluorinated indoles. Cyclisation of tolans containing larger numbers of fluorine atoms in their rings proceeds most efficiently in the presence of KOH, resulting in 2-phenylindoles containing the current maximum of eight fluorine atoms.
PALLADIUM(II)-CATALYZED SELECTIVE FLUORINATION OF BENZOIC ACIDS AND DERIVATIVES
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Paragraph 0135; 0136, (2014/02/16)
A new method of ortho-fluorination for selectively fluorinating a benzoic acid or derivative compound where an aryl C—H bond is directly replaced by an aryl C—F bond is provided. The method comprises reacting a compound having the formula: wherein X is at
Continuous flow synthesis of difluoroamine systems by direct fluorination
McPake, Christopher B.,Murray, Christopher B.,Sandford, Graham
, p. 145 - 150 (2013/04/10)
Continuous flow methodology for the synthesis of perfluoroaryl difluoroamine derivatives by reaction of fluorine gas with an appropriate perfluoroaniline substrate is described, further demonstrating the efficient use of flow regimes for reactions involvi
Pd(II)-catalyzed cross-coupling of C(sp2)h bonds and alkyl, aryl, and vinylboron reagents via Pd(II)/Pd(0) catalysis
Wasa, Masayuki,Chan, Kelvin S. L.,Yu, Jin-Quan
supporting information; experimental part, p. 1004 - 1006 (2011/12/05)
Pd(II)-catalyzed cross-coupling of ortho-CH bonds in benzoic acid and phenylacetic acid amides with alkyl, aryl, and vinylboron reagents have been achieved via Pd(II)/Pd(0) catalysis, demonstrating the unprecedented versatility of CH activation reactions.
Palladium(II)-catalyzed selective monofluorination of benzoic acids using a practical auxiliary: A weak-coordination approach
Chan, Kelvin S. L.,Wasa, Masayuki,Wang, Xisheng,Yu, Jin-Quan
supporting information; experimental part, p. 9081 - 9084 (2011/10/17)
Finally, a choice! A highly selective palladium(II)-catalyzed ortho-monofluorination reaction has been achieved for the first time through a weak coordination (see scheme; Ar=2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl) . Simple modification of this protocol allows for a choice between mono- and difluorination. The mono- and difluorinated benzoic acid derivatives are valuable in the pharmaceutical and agrochemical industries. Copyright
Mechanisms of reactions of halogenated compounds. Part 7. Effects of fluorine and other groups as substituents on nucleophilic aromatic substitution
Chambers, Richard D.,Martin, Peter A.,Sandford, Graham,Williams, D. Lyn H.
scheme or table, p. 998 - 1002 (2009/04/04)
The effect of fluorine as a substituent group on nucleophilic aromatic substitution is discussed, where a fluorine atom located ortho to the point of substitution may be of variable activating influence, whereas fluorine located para is slightly deactivat
Synthesis of vinylsulfanyl-substitued polyfluorobenzenes from perfluorotoluene
Amosova,Gavrilova,Afonin
, p. 402 - 405 (2007/10/03)
The reaction of octafluorotoluene in DMF with vinylthiolate ion generated from divinyl sulfide by the action of sodium in liquid ammonia afforded 2,3,5,6-tetrafluoro-4-trifluoromethylaniline, 3,6-difluoro-4-trifluoromethyl-1, 2,5-tris(vinylsulfanyl)benzen
