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Search for "halogen bond donor" in Full Text gives 8 result(s) in Beilstein Journal of Organic Chemistry.
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
- Periklis X. Kolagkis,
- Eirini M. Galathri and
- Christoforos G. Kokotos
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
- (Scheme 10). With catalyst 26 prepared, its use was then studied as a halogen-bond donor in the catalytic synthesis of 28 (Scheme 11) [93][94]. Having identified the optimum reaction conditions, the general applicability was studied by reacting various indoles with a range of aldehydes and ketones to
- produce a wide range of bis(indolyl)methanes 28 in good to excellent yields (62–93%) [93][94]. Regarding the mechanism of action of this methodology, two halogen bonds are formed between the bidentate halogen-bond donor 26 and the oxygen of the carbonyl group (Scheme 12). This increases the
- excellent yields (85–98%) in a more facile manner. The reaction mechanism is similar to other halogen-bond donor catalysts (Scheme 14). While the broad substrate scope is a crucial benefit of this approach, the use of a toxic solvent and the slow reaction rates were some of the drawbacks that would need to
Graphical Abstract
Scheme 1: Examples of BIMs used for their medicinal properties.
Scheme 2: Mechanisms for the synthesis of BIMs using protic or Lewis acids as catalysts.
Scheme 3: Synthesis of bis(indolyl)methanes using DBDMH.
Scheme 4: Competition experiments and synthesis of bis(indolyl)methanes using DBDMH.
Scheme 5: Proposed mechanism for formation of BIM of using DBDMH.
Scheme 6: Synthesis of bis(indolyl)methanes using I2.
Scheme 7: General reaction mechanism upon halogen bonding.
Scheme 8: Synthesis of bis(indolyl)methanes using I2, introduced by Ji.
Scheme 9: Synthesis of bis(indolyl)methanes using Br2 in CH3CN.
Scheme 10: Βidentate halogen-bond donors.
Scheme 11: Synthesis of bis(indolyl)methanes using bidentate halogen-bond donor 26.
Scheme 12: Proposed reaction mechanism.
Scheme 13: Synthesis of bis(indolyl)methanes using iodoalkyne as catalyst.
Scheme 14: Proposed reaction mechanism.
Scheme 15: Optimized reaction conditions used by Ramshini.
Scheme 16: Activation of the carbonyl group by HPA/TPI-Fe3O4.
Scheme 17: Synthesis of BIMs in the presence of nanoAg-Pt/SiO2-doped silicate.
Scheme 18: Mechanism of action proposed by Khalafi-Nezhad et al.
Scheme 19: Activation of the carbonyl group by the Cu–isatin Schiff base complex.
Scheme 20: Optimum reaction conditions published by Jain.
Scheme 21: Organocatalytic protocol utilizing nanoparticles introduced by Bankar.
Scheme 22: Activation of the carbonyl group by the AlCl3·6H2O-SDS-SiO2 complex.
Scheme 23: Optimal reaction conditions for the aforementioned nano-Fe3O4 based catalysts.
Scheme 24: Nanocatalytic protocol proposed by Kaur et al.
Scheme 25: Microwave approach introduced by Yuan.
Scheme 26: Microwave approach introduced by Zahran et al.
Scheme 27: Microwave irradiation protocol introduced by Bindu.
Scheme 28: Silica-supported microwave irradiation protocol.
Scheme 29: Proposed mechanism for formation of BIM by Nongkhlaw.
Scheme 30: Microwave-assisted synthesis of BIMs catalyzed by succinic acid.
Scheme 31: Proposed mechanism of action of MMO-4.
Scheme 32: Catalytic approach introduced by Muhammadpoor-Baltork et al.
Scheme 33: Reaction conditions used by Xiao-Ming.
Scheme 34: Ultrasonic irradiation-based protocol published by Saeednia.
Scheme 35: Pyruvic acid-mediated synthesis of BIMs proposed by Thopate.
Scheme 36: Synthesis of BIMs using [bmim]BF4 or [bmim]PF6 ionic liquids.
Scheme 37: Synthesis of BIMs utilizing In(OTf)3 in octylmethylimidazolium hexafluorophosphate as ionic liquid.
Scheme 38: FeCl3·6H2O-catalyzed synthesis of BIMs with use of ionic liquid.
Scheme 39: Synthesis of BIMs utilizing the [hmim]HSO4/EtOH catalytic system.
Scheme 40: Synthesis of BIMs utilizing acidic ionic liquid immobilized on silica gel (ILIS-SO2Cl).
Scheme 41: The [bmim][MeSO4]-catalyzed reaction of indole with various aldehydes.
Scheme 42: The role of [bmim][MeSO4] in catalyzing the reaction of indole with aldehydes.
Scheme 43: Synthesis of BIMs utilizing FeCl3-based ionic liquid ([BTBAC]Cl-FeCl3) as catalyst.
Scheme 44: Synthesis of BIMs using [Msim]Cl at room temperature.
Scheme 45: [Et3NH][H2PO4]-catalyzed synthesis of bis(indolyl)methanes.
Scheme 46: PILs-catalyzed synthesis of bis(indolyl)methanes.
Scheme 47: FSILs-mediated synthesis of bis(indolyl)methanes.
Scheme 48: Possible “release and catch” catalytic process.
Scheme 49: Synthesis of bis(indolyl)methanes by [DABCO-H][HSO4].
Scheme 50: Synthesis of bis(indolyl)methanes by [(THA)(SO4)].
Scheme 51: Synthesis of BBSI-Cl and BBSI-HSO4.
Scheme 52: Synthesis of BIMs in the presence of BBSI-Cl and BBSI-HSO4.
Scheme 53: Chemoselectivity of the present method.
Scheme 54: Synthesis of BIMs catalyzed by chitosan-supported ionic liquid.
Scheme 55: Proposed mechanism of action of CSIL.
Scheme 56: Optimization of the reaction in DESs.
Scheme 57: Synthesis of BIMs using ChCl/SnCl2 as DES.
Scheme 58: Synthesis of BIMs derivatives in presence of DES.
Scheme 59: BIMs synthesis in choline chloride/urea (CC/U).
Scheme 60: Flow chemistry-based synthesis of BIMs by Ley.
Scheme 61: Flow chemistry-based synthesis of BIMs proposed by Nam et al.
Scheme 62: Amino-catalyzed reaction of indole with propionaldehyde.
Scheme 63: Aminocatalytic synthesis of BIMs.
Scheme 64: Proposed mechanism for the aminocatalytic synthesis of BIMs.
Scheme 65: Enzymatic reaction of indole with aldehydes.
Scheme 66: Proposed mechanism for the synthesis of BIMs catalyzed by TLIM.
Scheme 67: Proposed reaction mechanism by Badsara.
Scheme 68: Mechanism proposed by D’Auria.
Scheme 69: Photoinduced thiourea catalysis.
Scheme 70: Proposed mechanism of photoacid activation.
Scheme 71: Proposed mechanism of action for CF3SO2Na.
Scheme 72: Proposed mechanism for the synthesis of BIMs by Mandawad.
Scheme 73: Proposed mechanism for the (a) acid generation and (b) synthesis of BIMs.
Scheme 74: a) Reaction conditions employed by Khaksar and b) activation of the carbonyl group by HFIP.
Scheme 75: Activation of the carbonyl group by the PPy@CH2Br through the formation of a halogen bond.
Scheme 76: Reaction conditions utilized by Mhaldar et al.
Scheme 77: a) Reaction conditions employed by López and b) activation of the carbonyl group by thiourea.
Scheme 78: Infrared irradiation approach introduced by Luna-Mora and his research group.
Scheme 79: Synthesis of BIMs with the use of the Fe–Zn BMOF.
Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control
- Carlee A. Montgomery and
- Graham K. Murphy
Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86
- pattern shown in Figure 1, where R is the host atom or functional group to which the halogen is covalently bound, where X is the halogen atom possessing the σ-hole (halogen bond donor), and where Y is the Lewis base (halogen bond acceptor) [31]. σ-Holes arise from anisotropic covalent bonds between the
- more complex theories as to why such adducts evolve differently. As previously stated, the strength of a halogen bond interaction is impacted by various factors (e.g., electrostatics, charge transfer abilities, dispersion), where the extent of their influence depends on both the halogen bond donor and
Graphical Abstract
Figure 1: Generic representation of halogen bonding.
Figure 2: Quantitative evaluation of σ-holes in monovalent iodine-containing compounds; and, qualitative mole...
Figure 3: Quantitative evaluation of σ-holes in hypervalent iodine-containing molecules; and, qualitative MEP...
Figure 4: Quantitative evaluation of σ-holes in iodonium ylides; and, qualitative MEP map of I-12 from −0.083...
Scheme 1: Outline of possible reaction pathways between iodonium ylides and Lewis basic nucleophiles (top); a...
Scheme 2: Metal-free cyclopropanations of iodonium ylides, either as intermolecular (a) or intramolecular pro...
Figure 5: Zwitterionic mechanism for intramolecular cyclopropanation of iodonium ylides (left); and, stepwise...
Scheme 3: Metal-free intramolecular cyclopropanation of iodonium ylides.
Figure 6: Concerted cycloaddition pathway for the metal-free, intramolecular cyclopropanation of iodonium yli...
Scheme 4: Reaction of ylide 6 with diphenylketene to form lactone 24 and 25.
Figure 7: Nucleophilic (top) and electrophilic (bottom) addition pathways proposed by Koser and Hadjiarapoglo...
Scheme 5: Indoline synthesis from acyclic iodonium ylide 31 and tertiary amines.
Scheme 6: N-Heterocycle synthesis from acyclic iodonium ylide 31 and secondary amines.
Figure 8: Proposed mechanism for the formation of 33a from iodonium ylides and amines, involving an initial h...
Scheme 7: Indoline synthesis from acyclic iodonium ylides 39 and tertiary amines under blue light photocataly...
Scheme 8: Metal-free cycloproponation of iodonium ylides under blue LED irradiation. aUsing trans-β-methylsty...
Figure 9: Proposed mechanism of the cyclopropanation between iodonium ylides and alkenes under blue LED irrad...
Scheme 9: Formal C–H alkylation of iodonium ylides by nucleophilic heterocycles under blue LED irradiation.
Figure 10: Proposed mechanism of the formal C–H insertion of pyrrole under blue LED irradiation.
Scheme 10: X–H insertions between iodonium ylides and carboxylic acids, phenols and thiophenols.
Figure 11: Mechanistic proposal for the X–H insertion reactions of iodonium ylides.
Scheme 11: Radiofluorination of biphenyl using iodonium ylides 54a–e derived from various β-dicarbonyl auxilia...
Scheme 12: Radiofluorination of arenes using spirocycle-derived iodonium ylides 56.
Scheme 13: Radiofluorination of arenes using SPIAd-derived iodonium ylides 58.
Figure 12: Calculated reaction coordinate for the radiofluorination of iodonium ylide 60.
Scheme 14: Radiofluorination of iodonium ylides possessing various ortho- and para-substituents on the iodoare...
Figure 13: Difference in Gibbs activation energy for ortho- or para-anisyl derived iodonium ylides 63a and 63b....
Figure 14: Proposed equilibration of intermediates to transit between 64a (the initial adduct formed between 6...
Scheme 15: Comparison of 31 and ortho-methoxy iodonium ylide 39 in rhodium-catalyzed cyclopropanation and cycl...
Figure 15: X-ray crystal structure of dimeric 39 [6], (CCDC# 893474) [143,144].
Scheme 16: Enaminone synthesis using diazonium and iodonium ylides.
Figure 16: Transition state calculations for enaminone synthesis from iodonium ylides and thioamides.
Scheme 17: The reaction between ylides 73a–f and N-methylpyrrole under 365 nm UV irradiation.
Figure 17: Crystal structures of 76c (top) and 76e (bottom) [101], (CCDC# 2104180 & 2104181) [143,144].
Halides as versatile anions in asymmetric anion-binding organocatalysis
- Lukas Schifferer,
- Martin Stinglhamer,
- Kirandeep Kaur and
- Olga García Macheño
Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145
- -trifluorophenyl-type catalysts [45]. Additionally, the first asymmetric systems involving purely halogen bond donor catalysis have recently been developed by the groups of Huber [46] and García Mancheño [47]. Moreover, though chloride as halide counter-anion still being particularly prominent, the application of
Graphical Abstract
Figure 1: a) Binding interactions in the chloride channel of E. coli. and b) examples of chloride, cyanide, n...
Figure 2: a) H-bond vs anion-binding catalysis and b) activation modes in anion-binding catalysis.
Scheme 1: First proposed anion-binding mechanism in the thiourea-catalyzed acetalization of benzaldehyde.
Scheme 2: a) Thiourea-catalyzed enantioselective acyl-Pictet–Spengler reaction of tryptamine-derived imines 4...
Scheme 3: Proposed mechanism of the thiourea-catalyzed enantioselective Pictet–Spengler reaction of hydroxyla...
Scheme 4: a) Thiourea-catalyzed intramolecular Pictet–Spengler-type cyclization of hydroxylactam-derived N-ac...
Scheme 5: Enantioselective Reissert-type reactions of a) (iso)quinolines with silyl ketene acetals, and b) vi...
Figure 3: Role of the counter-anion: a) Anion acting as a spectator and b) anion participating directly as th...
Scheme 6: Enantioselective selenocyclization catalyzed by squaramide 28.
Scheme 7: Desymmetrization of meso-aziridines catalyzed by bifunctional thiourea catalyst 31.
Scheme 8: Anion-binding-catalyzed desymmetrization of a) meso-aziridines catalyzed by chiral triazolium catal...
Scheme 9: Bis-urea-catalyzed enantioselective fluorination of a) β-bromosulfides and b) β-haloamines by Gouve...
Scheme 10: a) Bifunctional thiourea anion-binding – basic/nucleophilic catalysts. Selected applications in b) ...
Scheme 11: Thiourea-catalyzed enantioselective polycyclization reaction of hydroxylactams 51 through cation–π ...
Scheme 12: Enantioselective aza-Sakurai cyclization of hydroxylactams 56 implicating additional cation–π and L...
Scheme 13: Enantioselective tail-to-head cyclization of neryl chloride derivatives.
Scheme 14: Cation–π interactions in anion binding-catalyzed asymmetric addition reactions: a) addition of indo...
Scheme 15: Bisthiourea catalyzed oxa-Pictet–Spengler reaction of indole-based alcohols and aromatic aldehydes ...
Scheme 16: Anion-binding catalyst development in the enantioselective addition of silyl ketene acetals to 1-ch...
Scheme 17: a) Macrocyclic bis-thiourea catalyst in a diastereoselective glycosylation reaction. b) Competing SN...
Scheme 18: a) Folding mechanism of oligotriazoles upon anion recognition. b) Representative tetratriazole 82 c...
Scheme 19: Switchable chiral tetratriazole catalyst 86 in the enantioselective addition of silyl ketene acetal...
Synthetic reactions driven by electron-donor–acceptor (EDA) complexes
- Zhonglie Yang,
- Yutong Liu,
- Kun Cao,
- Xiaobin Zhang,
- Hezhong Jiang and
- Jiahong Li
Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67
- considered as a specific EDA complex [62]. In 2016, Yu and colleagues [33] employed perfluoroalkyl iodide 6 as halogen-bond donor (electron acceptor) and the organic base dibenzylamine as the halogen-bond acceptor (electron donor) to form the XB complex 8, and then a fluoroalkyl radical was given via visible
Graphical Abstract
Scheme 1: The electron transfer process in EDA complexes.
Scheme 2: Synthesis of benzo[b]phosphorus oxide 3 initiated by an EDA complex.
Scheme 3: Mechanism of the synthesis of quinoxaline derivative 7.
Scheme 4: Synthesis of imidazole derivative 10 initiated by an EDA complex.
Scheme 5: Synthesis of sulfamoylation product 12 initiated by an EDA complex.
Scheme 6: Mechanism of the synthesis of sulfamoylation product 12.
Scheme 7: Synthesis of indole derivative 22 initiated by an EDA complex.
Scheme 8: Synthesis of perfluoroalkylated pyrimidines 26 initiated by an EDA complex.
Scheme 9: Synthesis of phenanthridine derivative 29 initiated by an EDA complex.
Scheme 10: Synthesis of cis-tetrahydroquinoline derivative 32 initiated by an EDA complex.
Scheme 11: Mechanism of the synthesis of cis-tetrahydroquinoline derivative 32.
Scheme 12: Synthesis of phenanthridine derivative 38 initiated by an EDA complex.
Scheme 13: Synthesis of spiropyrroline derivative 40 initiated by an EDA complex.
Scheme 14: Synthesis of benzothiazole derivative 43 initiated by an EDA complex.
Scheme 15: Synthesis of perfluoroalkyl-s-triazine derivative 45 initiated by an EDA complex.
Scheme 16: Synthesis of indoline derivative 47 initiated by an EDA complex.
Scheme 17: Mechanism of the synthesis of spirocyclic indoline derivative 47.
Scheme 18: Synthesis of cyclobutane product 50 initiated by an EDA complex.
Scheme 19: Mechanism of the synthesis of spirocyclic indoline derivative 50.
Scheme 20: Synthesis of 1,3-oxazolidine compound 59 initiated by an EDA complex.
Scheme 21: Synthesis of trifluoromethylated product 61 initiated by an EDA complex.
Scheme 22: Synthesis of indole alkylation product 64 initiated by an EDA complex.
Scheme 23: Synthesis of perfluoroalkylation product 67 initiated by an EDA complex.
Scheme 24: Synthesis of hydrotrifluoromethylated product 70 initiated by an EDA complex.
Scheme 25: Synthesis of β-trifluoromethylated alkyne product 71 initiated by an EDA complex.
Scheme 26: Mechanism of the synthesis of 2-phenylthiophene derivative 74.
Scheme 27: Synthesis of allylated product 80 initiated by an EDA complex.
Scheme 28: Synthesis of trifluoromethyl-substituted alkynyl product 84 initiated by an EDA complex.
Scheme 29: Synthesis of dearomatized fluoroalkylation product 86 initiated by an EDA complex.
Scheme 30: Mechanism of the synthesis of dearomatized fluoroalkylation product 86.
Scheme 31: Synthesis of C(sp3)–H allylation product 91 initiated by an EDA complex.
Scheme 32: Synthesis of perfluoroalkylation product 93 initiated by an EDA complex.
Scheme 33: Synthesis of spirocyclic indolene derivative 95 initiated by an EDA complex.
Scheme 34: Synthesis of perfluoroalkylation product 97 initiated by an EDA complex.
Scheme 35: Synthesis of alkylated indole derivative 100 initiated by an EDA complex.
Scheme 36: Mechanism of the synthesis of alkylated indole derivative 100.
Scheme 37: Synthesis of arylated oxidized indole derivative 108 initiated by an EDA complex.
Scheme 38: Synthesis of 4-ketoaldehyde derivative 111 initiated by an EDA complex.
Scheme 39: Mechanism of the synthesis of 4-ketoaldehyde derivative 111.
Scheme 40: Synthesis of perfluoroalkylated olefin 118 initiated by an EDA complex.
Scheme 41: Synthesis of alkylation product 121 initiated by an EDA complex.
Scheme 42: Synthesis of acylation product 123 initiated by an EDA complex.
Scheme 43: Mechanism of the synthesis of acylation product 123.
Scheme 44: Synthesis of trifluoromethylation product 126 initiated by an EDA complex.
Scheme 45: Synthesis of unnatural α-amino acid 129 initiated by an EDA complex.
Scheme 46: Synthesis of thioether derivative 132 initiated by an EDA complex.
Scheme 47: Synthesis of S-aryl dithiocarbamate product 135 initiated by an EDA complex.
Scheme 48: Mechanism of the synthesis of S-aryl dithiocarbamate product 135.
Scheme 49: Synthesis of thioether product 141 initiated by an EDA complex.
Scheme 50: Mechanism of the synthesis of borate product 144.
Scheme 51: Synthesis of boronation product 148 initiated by an EDA complex.
Scheme 52: Synthesis of boration product 151 initiated by an EDA complex.
Scheme 53: Synthesis of boronic acid ester derivative 154 initiated by an EDA complex.
Scheme 54: Synthesis of β-azide product 157 initiated by an EDA complex.
Scheme 55: Decarboxylation reaction initiated by an EDA complex.
Scheme 56: Synthesis of amidated product 162 initiated by an EDA complex.
Scheme 57: Synthesis of diethyl phenylphosphonate 165 initiated by an EDA complex.
Scheme 58: Mechanism of the synthesis of diethyl phenylphosphonate derivative 165.
Scheme 59: Synthesis of (Z)-2-iodovinyl phenyl ether 168 initiated by an EDA complex.
Scheme 60: Mechanism of the synthesis of (Z)-2-iodovinyl phenyl ether derivative 168.
Scheme 61: Dehalogenation reaction initiated by an EDA complex.
Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding
- Subrata Nath,
- Alexander Kappelt,
- Matthias Spengler,
- Bibhisan Roy,
- Jens Voskuhl and
- Michael Giese
Beilstein J. Org. Chem. 2021, 17, 124–131, doi:10.3762/bjoc.17.13
- groups employed halogen bonding for the formation of liquid crystalline materials [8][9]. For instance, Palacio et al. used (E)-1-(4-(octyloxy)phenyl)-2-(2,3,5,6-tetrafluoro-4-iodophenyl)diazene as a photo-switchable halogen bond donor and investigated the light-induced phase transition of the complexes
- fluorine substitution of the aromatic halogen bond donor on the liquid crystallinity and the photo-response of halogen-bonded liquid crystals [12]. However, all reported halogen-bonded liquid crystals rely on the halogen-bond-acceptor capability of pyridyl units and so far, no study on the fluorescence
- crystal is reported, employing the interaction between iodofluorobenzene derivatives and nitro-cyanostilbenes. A systematic investigation of the materials revealed the impact of the halogen bond donor on the liquid crystalline properties of the assemblies. While the stilbene-based halogen bond donor
Graphical Abstract
Figure 1: Schematic representation of the modular approach towards halogen-bonded fluorescent liquid crystals....
Figure 2: Representative POM images of NO2-C10 at 94 °C (a) and NO2-C10∙∙∙F4Az at 61.5 °C (b) upon cooling fr...
Figure 3: Comparison of the mesomorphic properties of NO2-Cn, NO2-Cn∙∙∙F4St, and NO2-Cn∙∙∙F4Az (n = 8–11). Th...
Figure 4: Graphical representation of the calculated interaction energies in kJ/mol of the XB-acceptor NO2-C1...
Figure 5: Summary of the thermal behaviour of the azo complexes with decreasing fluorination degree as observ...
Figure 6: POM images of the supramolecular assemblies NO2-C10∙∙∙F3Az (a), NO2-C10∙∙∙F2Az (b) and NO2-C10∙∙∙F2...
Figure 7: Fluorescence studies of NO2-C9∙∙∙F4St. The photographs of the solid components as well as the forme...
Figure 8: Photographs of the assemblies with different alkoxy chain lengths on the NO2-Cn moiety directly aft...
Figure 9: Temperature-dependent fluorescent images of NO2-C9∙∙∙F4St showing the enhancement of emission upon ...
Fluorinated azobenzenes as supramolecular halogen-bonding building blocks
- Esther Nieland,
- Oliver Weingart and
- Bernd M. Schmidt
Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197
- noncovalent interaction between a polarized halogen atom (the halogen bond donor) and a Lewis base (the halogen bond acceptor) [1][2]. A prominent example regarding the origin of halogen bonding can be found in inorganic solid-state chemistry. The structurally diverse group of polyiodides, with its rich
- structural chemistry is governed by halogen bonding, where I− and I3− are considered the nucleophilic (halogen bond acceptor) and I2 the electrophilic (halogen bond donor) subcomponent [3][4][5][6][7]. Neutral halogen bonds on the other hand can be generally described by R–X···Y, where R–X is the halogen
- most positive compared to that of A2 and A1. The evolution of the iodine potential follows our experimental observation with iodoethynylazobenzene A3 being the strongest halogen bond donor and A1 being the weakest, within this series [48]. For potential, reversible photochemical control of
Graphical Abstract
Scheme 1: a) Azobenzenes A1–3 employed in this study. b) U-shaped anthracene halogen bond acceptor bearing tw...
Figure 1: Electrostatic potential map at different isodensity values (B3LYP/ def2/TZVP/DGZVP optimized geomet...
Figure 2: Top: Vertical electronic absorption spectra of a) A2 and b) A3, calculated using TD-B3LYP/def2-TZVP...
Figure 3: a) Space-filling model of U1···A2. The kinked alignment of both the lutidine units of U1 and the az...
Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests
- Fangfang Pan,
- Mohadeseh Dashti,
- Michael R. Reynolds,
- Kari Rissanen,
- John F. Trant and
- Ngong Kodiah Beyeh
Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91
- chloride (2), and 1,4-diiodooctafluorobutane and accompanying small solvent guests (methanol, acetonitrile and water) are presented. The guests’ inclusion affects the geometry of the cavity of the receptors 1 and 2, while the divalent halogen bond donor 1,4-diiodooctafluorobutane determines the overall
- halogen bond acceptors [29][30][31][32][33][34]. We have previously shown that N-alkylammonium resorcinarene bromides (NARBrs) can form various halogen-bonded assemblies with the classical organic halogen bond donor 1,4-diiodooctafluorobutane (DIOFB) depending on the solvent, the presence of potential
Graphical Abstract
Figure 1: Tetravalent XB acceptor, Hex-NARBr 1, Cy-NARCl 2, divalent XB donor DIOFB, and guests MeCN, MeOH an...
Figure 2: The previously reported halogen-bonded complexes CHCl3@1&DIOFB (a), and MeOH@1&DIOFB (b). (c)The fi...
Figure 3: The two dimerization modes in the MeOH-MeCN@1&DIOFB complex. In both modes, the cavities are shown ...
Figure 4: (a) The halogen bonding (blue broken lines), hydrogen bonding (red broken lines) and the host–guest...
Figure 5: 19F NMR in CDCl3 at 298 K of: a) DIOFB (10 mM); b) 1:2 mixture of DIOFB and 1; 1:2:1 mixture of DIO...
Figure 6: 1H NMR in CDCl3 at 298 K of: a) 1 (10 mM), b) 1:2 mixture of 1 and DIOFB, c) 1:2:1 mixture of 1, DI...
New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation
- Pavel Nagorny and
- Zhankui Sun
Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283
- organic catalysts for electrophile activation through the formation of C–H hydrogen bonds and C–X halogen bonds. Keywords: C–H hydrogen bond; counteranion activation; electrophile activation; halogen bond donor; hydrogen bond donor; organocatalysis; Review Introduction Over the past century chemists
- during the catalytic process was supported by 13C and 19F NMR studies. Halogen bond donor organocatalysis based on aryl halides The pioneering study of Bolm has attracted significant attention and a number of important studies have emerged since then. In particular, the Huber group has contributed to the
- determined to be 3.5 × 106 M−1 (CH3CN). In addition to the aforementioned studies, recent results by Huber and Codée indicate that not only 1-chloroisochroman, but also more complex substrates such as 2,3,4,6-tetra-O-benzylglucosyl chloride could undergo halogen bond-donor-catalyzed solvolysis [86]. Further
Graphical Abstract
Figure 1: Electrophile Activation by Hydrogen Bond Donors [1-16].
Figure 2: Early examples of C–H hydrogen bonds and their recent use in supramolecular chemistry [18,19,32-34].
Scheme 1: Design of 1,2,3-triazole-based catalysts for trityl group transfer through chloride anion binding b...
Scheme 2: Examples of chiral triazole-based catalysts for anion activation designed by Mancheno and co-worker...
Scheme 3: Application of chiral triazole-based catalysts L3 and L4 for counterion activation of pyridinium, q...
Scheme 4: Ammonium salt anion binding via C–H hydrogen bonds in solid state [40-45,50,51].
Scheme 5: Early examples of ammonium salts being used for electrophilic activation of imines in aza-Diels–Ald...
Scheme 6: Ammonium salts as hydrogen bond-donor catalysts by Bibal and co-workers [53,54].
Scheme 7: Tetraalkylammonium catalyst (L6)-catalyzed dearomatization of isoquinolinium salts [50].
Scheme 8: Tetraalkylammonium catalyst L6 complexation to halogen-containing substrates [51].
Scheme 9: Tetraalkylammonium-catalyzed aza-Diels–Alder reaction by Maruoka and co-workers [52].
Scheme 10: (A) Alkylpyridinium catalysts L13-catalyzed reaction of 1-isochroman and silyl ketene acetals by Be...
Scheme 11: Mixed N–H/C–H two hydrogen bond donors L14 and L15 as organocatalysts for ROP of lactide by Bibal a...
Scheme 12: Examples of stable complexes based on halogen bonding [68,69].
Scheme 13: Interaction between (−)-sparteine hydrobromide and (S)-1,2-dibromohexafluoropropane in the cocrysta...
Scheme 14: Iodine-catalyzed reactions that are computationally proposed to proceed through halogen bond to car...
Scheme 15: Transfer hydrogenation of phenylquinolines catalyzed by haloperfluoroalkanes by Bolm and co-workers ...
Scheme 16: Halogen bond activation of benzhydryl bromides by Huber and co-workers [82].
Scheme 17: Halogen bond-donor-catalyzed addition to oxocarbenium ions by Huber and co-workers [89].
Scheme 18: Halogen bond-donor activation of α,β-unsaturated carbonyl compounds in the [2 + 4] cycloaddition re...
Scheme 19: Halogen bond donor activation of imines in the [2 + 4] cycloaddition reaction of imine and Danishef...
Scheme 20: Transfer hydrogenation catalyzed by a chiral halogen bond donor by Tan and co-workers [91].
Scheme 21: Allylation of benzylic alcohols by Takemoto and co-workers [92].
Scheme 22: NIS induced semipinacol rearrangement via C–X bond cleavage [93].
