Conformational impact of structural modifications in 2-fluorocyclohexanone

• Francisco A. Martins,
• Josué M. Silla and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2017, 13, 1781–1787, doi:10.3762/bjoc.13.172

• -fluorocyclohexanone; hyperconjugation; Introduction Organofluorine compounds are of special interest in materials, pharmaceutical and agricultural sciences, as the C–F bond is the most polar bond in organic chemistry, which can be useful in the design of performance organic molecules [1]. A fluorine substituent in

• organofluorine compounds affects conformational properties, since it can induce stereoelectronic effects, such as σC–H to σ*C–F hyperconjugative interactions in case of an antiparallel oriented C–H bond. This is the origin of the so-called 'gauche effect', because electronegative C–X bonds do not participate in

• hydrogen bond F···HN (e.g., dF···HN = 2.21 Å and F···H–N angle = 110.0°, when X/Y = CH2/NHZ), despite similar interactions hardly ever appear in organofluorine compounds when forming 5-membered rings [25][26]. In addition, it is also quite intuitive that fluorine tends to occupy the axial orientation in

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• fluoroalkylated aromatics. Keywords: β-carbon elimination; carbon–carbon bond cleavage; decarboxylation; tetrahedral intermediate; trifluoroacetate; fluoral; trifluoromethylation; Introduction Organofluorine compounds attract attention because of their applicability in various fields, such as medicine

• contributed to the advancement of human life and the global demand for organofluorine compounds will continue to increase. Therefore, the introduction of fluorine-containing functional groups into organic molecules is recognized as a general strategy for the design of drugs and functional materials. In fact

Coupling of α,α-difluoro-substituted organozinc reagents with 1-bromoalkynes

• Artem A. Zemtsov,
• Alexander D. Volodin,
• Vitalij V. Levin,
• Marina I. Struchkova and
• Alexander D. Dilman

Beilstein J. Org. Chem. 2015, 11, 2145–2149, doi:10.3762/bjoc.11.231

• dimethylformamide under ligand-free conditions. Keywords: 1-bromoalkynes; cross-coupling; organofluorine compounds; organozinc reagents; Introduction gem-Difluorinated organic compounds have attracted increasing attention nowadays due to their applicability in medicinal chemistry [1][2] and other fields. Indeed

Lewis acid-promoted hydrofluorination of alkynyl sulfides to generate α-fluorovinyl thioethers

• Davide Bello and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 1902–1909, doi:10.3762/bjoc.11.205

• Organofluorine compounds have found wide use in tuning the properties of performance compounds in medicinal and materials chemistry [1][2]. Also the electronegativity of fluorine has been used to design and tune steric and electronic mimetics of functional groups for applications in biomolecular chemistry. For

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• eventually open up for just such a possibility. Trifluoroacetic acid (CF3CO2H) has been known since 1922 [21], but its widespread application was only made possible sometime later, much due to the development of electrochemical fluorination processes (Simons process) for production of organofluorine

• compounds in the 1930s and 1940s [22][23]. It is a strong acid (pKa ≈ 0.5), quite volatile (bp. 72 °C) and miscible with water, fluorocarbons and most organic solvents [22]. In the late 1940s and throughout the 1950s, trifluoroacetic acid and trifluoroacetic anhydride were the subjects of a number of

Highly selective electrochemical fluorination of dithioacetal derivatives bearing electron-withdrawing substituents at the position α to the sulfur atom using poly(HF) salts

• Bin Yin,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2015, 11, 85–91, doi:10.3762/bjoc.11.12

• fluorine atom(s) into organic molecules very often improves or enhances their desired characteristic physical and biological properties hence organofluorine compounds are highly useful for medicinal, agrochemical, and materials science [1][2][3][4][5][6]. In order to prepare new fluorine compounds

Aminofluorination of 2-alkynylanilines: a Au-catalyzed entry to fluorinated indoles

• Antonio Arcadi,
• Emanuela Pietropaolo,
• Antonello Alvino and
• Véronique Michelet

Beilstein J. Org. Chem. 2014, 10, 449–458, doi:10.3762/bjoc.10.42

• ; indoles; tandem reactions; Introduction Introducing fluorine atoms into organic molecules still faces challenges in organic synthesis [1]. Organofluorine compounds found growing use in various areas including pharmaceuticals, agrochemicals, and materials [2]. A significant proportion of pharmaceuticals

Asymmetric allylic alkylation of Morita–Baylis–Hillman carbonates with α-fluoro-β-keto esters

• Lin Yan,
• Zhiqiang Han,
• Bo Zhu,
• Caiyun Yang,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2013, 9, 1853–1857, doi:10.3762/bjoc.9.216

• properties, compared with their parent compounds [1]. Due to the rareness of organofluorine compounds in nature, synthetic fluorinated compounds have been widely applied in numerous areas, including materials, agrochemicals, pharmaceuticals and fine chemicals [2][3][4]. In this context, the stereoselective

Recyclable fluorous cinchona alkaloid ester as a chiral promoter for asymmetric fluorination of β-ketoesters

• Wen-Bin Yi,
• Xin Huang,
• Zijuan Zhang,
• Dian-Rong Zhu,
• Chun Cai and
• Wei Zhang

Beilstein J. Org. Chem. 2012, 8, 1233–1240, doi:10.3762/bjoc.8.138

• compounds have unique properties because fluorine forms a strong carbon–fluorine bond with a small covalent radius and high electronegativity. Other than fluorinated polymers in materials science, organofluorine compounds have gained increasing popularity in medical chemistry and agricultural chemistry

Conformational analysis, stereoelectronic interactions and NMR properties of 2-fluorobicyclo[2.2.1]heptan-7-ols

• Fátima M. P. de Rezende,
• Marilua A. Moreira,
• Rodrigo A. Cormanich and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2012, 8, 1227–1232, doi:10.3762/bjoc.8.137

• as reactivity of a wide range of chemical and biological systems [1]. However, it has been argued that organic fluorine hardly ever participates in HB, due to the poor proton acceptor ability of the fluorine atom [2]; nevertheless, there are some instances of organofluorine compounds forming seven

• atom (θ = 330.0°) is the most stable structure in the gas phase (this structure will be further referred to as the global minimum). This suggests that a F∙∙∙HO intramolecular HB is operating and governs the stability of 5; however, different organofluorine compounds with similar orientation of the

• 1hJF,OH SSCC in this aliphatic organofluorine compound, and is the main factor responsible for the large value of 1hJF,OH in the global minimum. Some organofluorine compounds and the 2-fluorobicyclo[2.2.1]heptan-7-ols (5–8) theoretically studied in this work. Potential energy surfaces for the

The C–F bond as a conformational tool in organic and biological chemistry

• Luke Hunter

Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38

• Luke Hunter School of Chemistry, The University of Sydney, NSW 2006, Australia 10.3762/bjoc.6.38 Abstract Organofluorine compounds are widely used in many different applications, ranging from pharmaceuticals and agrochemicals to advanced materials and polymers. It has been recognised for many

• paucity of fluorinated molecules in nature, there are many synthetic (non-natural) organofluorine compounds with valuable biological activity. Of these, an interesting subset exploit the C–F bond specifically as a conformational tool and some examples of such molecules are examined below. Fluorinated

• reported in due course. Conclusion The conformations of organofluorine compounds are influenced by a number of stereoelectronic effects associated with the C–F bond, including dipole–dipole interactions, charge–dipole interactions and hyperconjugation. Knowledge of these conformational effects allows the

Enantioselective nucleophilic difluoromethylation of aromatic aldehydes with Me₃SiCF₂SO₂Ph and PhSO₂CF₂H reagents catalyzed by chiral quaternary ammonium salts

• Chuanfa Ni,
• Fang Wang and
• Jinbo Hu

Beilstein J. Org. Chem. 2008, 4, No. 21, doi:10.3762/bjoc.4.21

• −, the fluorine substitution being commonly on the carbanion center) to an electrophile, represents one of the major methods for the synthesis of organofluorine compounds [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In recent years, a few methods have been reported for the enantioselective