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Search for "boronic ester" in Full Text gives 30 result(s) in Beilstein Journal of Organic Chemistry.
Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes
- Ludovic Eberlin,
- Fabien Tripoteau,
- François Carreaux,
- Andrew Whiting and
- Bertrand Carboni
Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19
- gave access to the homoallylic alcohols 35 in 77–86% yields. Alternatively, the presence of an allylic boronic ester group in the cycloadduct 33 was exploited in carrying out first the addition to 4-nitrobenzaldehyde to afford 36. Further normal-electron demand [4 + 2]-cycloaddition step with N
- -phenylmaleimide furnished the single tricyclic compound 37 (Scheme 26). The initial boronic ester group of 38, the direct precursor of 32, can be also converted into a trifluoroborate substituent by treatment with KHF2 in MeOH/H2O to increase the reactivity of the dienyl moiety towards electron-poor dienophiles
Graphical Abstract
Scheme 1: 1-Boron-substituted 1,3-diene in a tandem cycloaddition [4 + 2]/allylboration sequence.
Scheme 2: Lewis acid catalyst in the tandem cycloaddition [4 + 2]/allylboration sequence.
Scheme 3: Synthesis of an advanced precursor of clerodin.
Scheme 4: Intramolecular Diels–Alder/allylboration sequence.
Scheme 5: Diastereoselective Diels–Alder reaction with N-phenylmaleimide and 4-phenyltriazoline-3,5-dione.
Scheme 6: Asymmetric synthesis of a α-hydroxyalkylcyclohexane.
Scheme 7: Tandem [4 + 2]-cycloaddition/allylboration of 3-silyloxy- and 4-alkoxy-dienyl boronates.
Scheme 8: Metal-mediated cycloisomerization/Diels–Alder reaction/allylboration sequence.
Scheme 9: Cobalt-catalyzed Diels–Alder/allylboration sequence.
Scheme 10: A two-step reaction sequence for the synthesis of tetrahydronaphthalenes 12.
Scheme 11: Tandem sequence based on the Petasis borono–Mannich reaction as first key step.
Scheme 12: One-pot tandem dimerization/allylboration reaction of 1,3-diene-2-boronate.
Scheme 13: Tandem Diels–Alder/cross-coupling reactions of trifluoroborates 15.
Scheme 14: Diels–Alder/cross-coupling reactions of 16.
Scheme 15: Metal catalyzed tandem Diels–Alder/hydrolysis reactions.
Scheme 16: Synthesis of anti-1,5-diols 18 by triple aldehyde addition.
Scheme 17: Catalytic enantioselective three-component hetero-[4 + 2]-cycloaddition/allylboration sequence.
Scheme 18: Synthesis of natural products using the catalytic enantioselective HDA/allylboration sequence.
Scheme 19: Total synthesis of a thiomarinol derivative.
Scheme 20: Synthesis of an advanced intermediate 27 for the east fragment of palmerolide A.
Scheme 21: Bicyclic piperidines from tandem aza-[4 + 2]-cycloaddition/allylboration.
Scheme 22: Hydrogenolysis reactions of hydrazinopiperidines.
Scheme 23: Tandem aza-[4 + 2]-cycloaddition/allylboration/retrosulfinyl-ene sequence.
Scheme 24: Boronated heterodendralene 32 in [4 + 2]-cycloadditions.
Scheme 25: Synthesis of tricyclic imides derivatives.
Scheme 26: Synthesis of 37 via a HDA/allylboration/DA sequence.
Scheme 27: Diels–Alder/allylboration sequence.
Incorporation of perfluorohexyl-functionalised thiophenes into oligofluorene-truxenes: synthesis and physical properties
- Neil Thomson,
- Alexander L. Kanibolotsky,
- Joseph Cameron,
- Tell Tuttle,
- Neil J. Findlay and
- Peter J. Skabara
Beilstein J. Org. Chem. 2013, 9, 1243–1251, doi:10.3762/bjoc.9.141
- then reacted with bis(pinacolato)diboron to afford boronic ester 8. The synthetic route to 2-iodo-4-perfluorohexylthiophene (13) (Scheme 2) began with treatment of 3-bromothiophene (1) with lithium bis(trimethylsilyl)amide and chlorotrimethylsilane to afford 2-trimethylsilyl-3-bromothiophene (9
- /ethanol solution. Lithiation and treatment with perfluorohexyliodide afforded 12, which was deprotected with tetrabutylammonium fluoride to afford 13. The boronic ester 16 was then synthesised by the same steps applied to obtain compound 8 (see Scheme 1). T1-3FTh and T1-4FTh were then synthesised by
- Suzuki coupling of tribromohexahexyltruxene 17, which was synthesised according to our previously published method [14], and the relevant boronic ester, 8 or 16 (Scheme 3). T4-4FTh (Scheme 4) was synthesised by coupling compound 16 with T3Br. The latter compound was obtained by our previously published
Graphical Abstract
Figure 1: Labelled truxene and compounds T1 and T4.
Scheme 1: Synthesis of the thiophene-fluorene arm for the 3-isomer.
Scheme 2: Synthesis of the thiophene-fluorene arm for the 4-isomer.
Scheme 3: Coupling of arms to the truxene core.
Scheme 4: Synthesis of T4-4FTh.
Figure 2: Normalised absorbance (solid) and emission (dashed) of materials in solution (dichloromethane).
Figure 3: HOMO−1 (bottom, left), HOMO (bottom, right), LUMO (top, left) and LUMO+1 (top, right) of T1-3FTh.
Figure 4: HOMO−1 (bottom, left), HOMO (bottom, right), LUMO (top, left) and LUMO+1 (top, right) of T1-4FTh.
Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester
- Sarah L. Harding,
- Sebastian M. Marcuccio and
- G. Paul Savage
Beilstein J. Org. Chem. 2012, 8, 606–612, doi:10.3762/bjoc.8.67
- favouring the oxidation of carbon–boron bonds, which makes boronic ester chemistry chemoselective, is a constraint that potentially limits the utility of nitrile oxide cycloadditions in the presence of a boronic acid ester. 4-Formylphenylboronic acid pinacol ester 4 is commercially available or easily
Graphical Abstract
Scheme 1: Concept for library generation by dipolar cycloaddition followed by boronate coupling.
Scheme 2: General formation of alkyl (R) and aryl (Ar) nitrile oxides.
Scheme 3: Formation of 4-(aldoxime)phenylboronic acid pinacol ester 5.
Molecular recognition of organic ammonium ions in solution using synthetic receptors
- Andreas Späth and
- Burkhard König
Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32
Graphical Abstract
Figure 1: Biologically important amines and quaternary ammonium salts: histamine (1), dopamine (2) and acetyl...
Figure 2: Crown ether 18-crown-6.
Figure 3: Conformations of 18-crown-6 (4) in solvents of different polarity.
Figure 4: Binding topologies of the ammonium ion depending on the crown ring size.
Figure 5: A “pseudorotaxane” structure consisting of 24-crown-8 and a secondary ammonium ion (5); R = Ph.
Figure 6: Typical examples of azacrown ethers, cryptands and related aza macrocycles.
Figure 7: Binding of ammonium to azacrown ethers and cryptands [111-113].
Figure 8: A 19-crown-6-ether with decalino blocking groups (11) and a thiazole-dibenzo-18-crown-6-ether (12).
Figure 9: 1,3-Bis(6-oxopyridazin-1-yl)propane derivatives 13 and 14 by Campayo et al.
Figure 10: Fluorescent azacrown-PET-sensors based on coumarin.
Figure 11: Two different pyridino-cryptands (17 and 18) compared to a pyridino-crown (19); chiral ammonium ion...
Figure 12: Pyridino-18-crown-6 ligand (21), a similar acridino-18-crown-6 ligand (22) and a structurally relat...
Figure 13: Ciral pyridine-azacrown ether receptors 24.
Figure 14: Chiral 15-crown-5 receptors 26 and an analogue 18-crown-6 ligand 27 derived from amino alcohols.
Figure 15: C2-symmetric chiral 18-crown-6 amino alcohol derivatives 28 and related macrocycles.
Figure 16: Macrocycles with diamide-diester groups (30).
Figure 17: C2-symmetric chiral aza-18-crown-6 ethers (31) with phenethylamine residues.
Figure 18: Chiral C-pivot p-methoxy-phenoxy-lariat ethers.
Figure 19: Chiral lariat crown ether 34.
Figure 20: Sucrose-based chiral crown ether receptors 36.
Figure 21: Permethylated fructooligosaccharide 37 showing induced-fit chiral recognition.
Figure 22: Biphenanthryl-18-crown-6 derivative 38.
Figure 23: Chiral lariat crown ethers derived from binol by Fuji et al.
Figure 24: Chiral phenolic crown ether 41 with “aryl chiral barriers” and guest amines.
Figure 25: Chiral bis-crown receptor 43 with a meso-ternaphthalene backbone.
Figure 26: Chromogenic pH-dependent bis-crown chemosensor 44 for diamines.
Figure 27: Triamine guests for binding to receptor 44.
Figure 28: Chiral bis-crown phenolphthalein chemosensors 46.
Figure 29: Crown ether amino acid 47.
Figure 30: Luminescent receptor 48 for bis-alkylammonium guests.
Figure 31: Luminescent CEAA (49a), a bis-CEAA receptor for amino acids (49b) and the structure of lysine bindi...
Figure 32: Luminescent CEAA tripeptide for binding small peptides.
Figure 33: Bis crown ether 51a self assembles co-operatively with C60-ammonium ion 51b.
Figure 34: Triptycene-based macrotricyclic dibenzo-[24]-crown-8 ether host 52 and guests.
Figure 35: Copper imido diacetic acid azacrown receptor 53a and the suggested His-Lys binding motif; a copper ...
Figure 36: Urea (54) and thiourea (55) benzo crown receptor for transport and extraction of amino acids.
Figure 37: Crown pyryliums ion receptors 56 for amino acids.
Figure 38: Ditopic sulfonamide bridged crown ether receptor 57.
Figure 39: Luminescent peptide receptor 58.
Figure 40: Luminescent receptor 59 for the detection of D-glucosamine hydrochloride in water/ethanol and lumin...
Figure 41: Guanidinium azacrown receptor 61 for simple amino acids and ditopic receptor 62 with crown ether an...
Figure 42: Chiral bicyclic guanidinium azacrown receptor 63 and similar receptor 64 for the enantioselective t...
Figure 43: Receptors for zwitterionic species based on luminescent CEAAs.
Figure 44: 1,10-Azacrown ethers with sugar podand arms and the anticancer agent busulfan.
Figure 45: Benzo-18-crown-6 modified β-cyclodextrin 69 and β-cyclodextrin functionalized with diaza-18-crown-6...
Figure 46: Receptors for colorimetric detection of primary and secondary ammonium ions.
Figure 47: Porphyrine-crown-receptors 72.
Figure 48: Porphyrin-crown ether conjugate 73 and fullerene-ammonium ion guest 74.
Figure 49: Calix[4]arene (75a), homooxocalix[4]arene (75b) and resorcin[4]arene (75c) compared (R = H, alkyl c...
Figure 50: Calix[4]arene and ammonium ion guest (R = H, alkyl, OAcyl etc.), possible binding sites; A: co-ordi...
Figure 51: Typical guests for studies with calixarenes and related molecules.
Figure 52: Lower rim modified p-tert-butylcalix[5]arenes 82.
Figure 53: The first example of a water soluble calixarene.
Figure 54: Sulfonated water soluble calix[n]arenes that bind ammonium ions.
Figure 55: Displacement assay for acetylcholine (3) with a sulfonato-calix[6]arene (84b).
Figure 56: Amino acid inclusion in p-sulfonatocalix[4]arene (84a).
Figure 57: Calixarene receptor family 86 with upper and lower rim functionalization.
Figure 58: Calix[6]arenes 87 with one carboxylic acid functionality.
Figure 59: Sulfonated calix[n]arenes with mono-substitution at the lower rim systematically studied on their r...
Figure 60: Cyclotetrachromotropylene host (91) and its binding to lysine (81c).
Figure 61: Calixarenes 92 and 93 with phosphonic acids groups.
Figure 62: Calix[4]arene tetraphosphonic acid (94a) and a double bridged analogue (94b).
Figure 63: Calix[4]arene tetraphosphonic acid ester (92c) for surface recognition experiments.
Figure 64: Calixarene receptors 95 with α-aminophosphonate groups.
Figure 65: A bridged homocalix[3]arene 95 and a distally bridged homocalix[4]crown 96.
Figure 66: Homocalix[3]arene ammonium ion receptor 97a and the Reichardt’s dye (97b) for colorimetric assays.
Figure 67: Chromogenic diazo-bridged calix[4]arene 98.
Figure 68: Calixarene receptor 99 by Huang et al.
Figure 69: Calixarenes 100 reported by Parisi et al.
Figure 70: Guest molecules for inclusion in calixarenes 100: DAP × 2 HCl (101a), APA (101b) and Lys-OMe × 2 HC...
Figure 71: Different N-linked peptido-calixarenes open and with glycol chain bridges.
Figure 72: (S)-1,1′-Bi-2-naphthol calixarene derivative 104 published by Kubo et al.
Figure 73: A chiral ammonium-ion receptor 105 based on the calix[4]arene skeleton.
Figure 74: R-/S-phenylalaninol functionalized calix[6]arenes 106a and 106b.
Figure 75: Capped homocalix[3]arene ammonium ion receptor 107.
Figure 76: Two C3 symmetric capped calix[6]arenes 108 and 109.
Figure 77: Phosphorous-containing rigidified calix[6]arene 110.
Figure 78: Calix[6]azacryptand 111.
Figure 79: Further substituted calix[6]azacryptands 112.
Figure 80: Resorcin[4]arene (75c) and the cavitands (113).
Figure 81: Tetrasulfonatomethylcalix[4]resorcinarene (114).
Figure 82: Resorcin[4]arenes (115a/b) and pyrogallo[4]arenes (115c, 116).
Figure 83: Displacement assay for acetylcholine (3) with tetracyanoresorcin[4]arene (117).
Figure 84: Tetramethoxy resorcinarene mono-crown-5 (118).
Figure 85: Components of a resorcinarene based displacement assay for ammonium ions.
Figure 86: Chiral basket resorcin[4]arenas 121.
Figure 87: Resorcinarenes with deeper cavitand structure (122).
Figure 88: Resorcinarene with partially open deeper cavitand structure (123).
Figure 89: Water-stabilized deep cavitands with partially structure (124, 125).
Figure 90: Charged cavitands 126 for tetralkylammonium ions.
Figure 91: Ditopic calix[4]arene receptor 127 capped with glycol chains.
Figure 92: A calix[5]arene dimer for diammonium salt recognition.
Figure 93: Calixarene parts 92c and 129 for the formation molecular capsules.
Figure 94: Encapsulation of a quaternary ammonium cation by two resorcin[4]arene molecules (NMe4+@[75c]2 × Cl−...
Figure 95: Encapsulation of a quaternary ammonium cation by six resorcin[4]arene molecules (NMe3D+@[130]6 × Cl−...
Figure 96: Structure and schematic of cucurbit[6]uril (CB[6], 131a).
Figure 97: Cyclohexanocucurbit[6]uril (CB′[6], 132) and the guest molecule spermine (133).
Figure 98: α,α,δ,δ-Tetramethylcucurbit[6]uril (134).
Figure 99: Structure of the cucurbituril-phthalhydrazide analogue 135.
Figure 100: Organic cavities for the displacement assay for amine differentiation.
Figure 101: Displacement assay methodology for diammonium- and related guests involving cucurbiturils and some ...
Figure 102: Nor-seco-Cucurbituril (±)-bis-ns-CB[6] (140) and guest molecules.
Figure 103: The cucurbit[6]uril based complexes 141 for chiral discrimination.
Figure 104: Cucurbit[7]uril (131c) and its ferrocene guests (142) opposed.
Figure 105: Cucurbit[7]uril (131c) guest inclusion and representative guests.
Figure 106: Cucurbit[7]uril (131c) binding to succinylcholine (145) and different bis-ammonium and bis-phosphon...
Figure 107: Paraquat-cucurbit[8]uril complex 149.
Figure 108: Gluconuril-based ammonium receptors 150.
Figure 109: Examples of clefts (151a), tweezers (151b, 151c, 151d) and clips (151e).
Figure 110: Kemp’s triacid (152a), on example of Rebek’s receptors (152b) and guests.
Figure 111: Amino acid receptor (154) by Rebek et al.
Figure 112: Hexagonal lattice designed hosts by Bell et al.
Figure 113: Bell’s amidinium receptor (156) and the amidinium ion (157).
Figure 114: Aromatic phosphonic acids.
Figure 115: Xylene phosphonates 159 and 160a/b for recognition of amines and amino alcohols.
Figure 116: Bisphosphonate recognition motif 161 for a colorimetric assay with alizarin complexone (163) for ca...
Figure 117: Bisphosphonate/phosphate clip 164 and bisphosphonate cleft 165.
Figure 118: N-Methylpyrazine 166a, N-methylnicotinamide iodide (166b) and NAD+ (166c).
Figure 119: Bisphosphate cavitands.
Figure 120: Bisphosphonate 167 of Schrader and Finocchiaro.
Figure 121: Tweezer 168 for noradrenaline (80b).
Figure 122: Different tripods and heparin (170).
Figure 123: Squaramide based receptors 172.
Figure 124: Cage like NH4+ receptor 173 of Kim et al.
Figure 125: Ammonium receptors 174 of Chin et al.
Figure 126: 2-Oxazolin-based ammonium receptors 175a–d and 176 by Ahn et al.
Figure 127: Racemic guest molecules 177.
Figure 128: Tripods based on a imidazole containing macrocycle (178) and the guest molecules employed in the st...
Figure 129: Ammonium ion receptor 180.
Figure 130: Tetraoxa[3.3.3.3]paracyclophanes 181 and a cyclophanic tetraester (182).
Figure 131: Peptidic bridged paraquat-cyclophane.
Figure 132: Shape-selective noradrenaline host.
Figure 133: Receptor 185 for binding of noradrenaline on surface layers from Schrader et al.
Figure 134: Tetraphosphonate receptor for binding of noradrenaline.
Figure 135: Tetraphosphonate 187 of Schrader and Finocchiaro.
Figure 136: Zinc-Porphyrin ammonium-ion receptors 188 and 189 of Mizutani et al.
Figure 137: Zinc porphyrin receptor 190.
Figure 138: Zinc porphyrin receptors 191 capable of amino acid binding.
Figure 139: Zinc-porphyrins with amino acid side chains for stereoinduction.
Figure 140: Bis-zinc-bis-porphyrin based on Tröger’s base 193.
Figure 141: BINAP-zinc-prophyrin derivative 194 and it’s guests.
Figure 142: Bisaryl-linked-zinc-porphyrin receptors.
Figure 143: Bis-zinc-porphyrin 199 for diamine recognition and guests.
Figure 144: Bis-zinc-porphyrin crown ether 201.
Figure 145: Bis-zinc-porphyrin 202 for stereodiscrimination (L = large substituent; S = small substituent).
Figure 146: Bis-zinc-porphyrin[3]rotaxane and its copper complex and guests.
Figure 147: Dien-bipyridyl ligand 206 for co-ordination of two metal atoms.
Figure 148: The ligand and corresponding tetradentate co-complex 207 serving as enantioselective receptor for a...
Figure 149: Bis(oxazoline)–copper(II) complex 208 for the recognition of amino acids in aqueous solution.
Figure 150: Zinc-salen-complexes 209 for the recognition tertiary amines.
Figure 151: Bis(oxazoline)–copper(II) 211 for the recognition of amino acids in aqueous solution.
Figure 152: Zn(II)-complex of a C2 terpyridine crown ether.
Figure 153: Displacement assay and receptor for aspartate over glutamate.
Figure 154: Chiral complex 214 for a colorimetric displacement assay for amino acids.
Figure 155: Metal complex receptor 215 with tripeptide side arms.
Figure 156: A sandwich complex 216 and its displaceable dye 217.
Figure 157: Lanthanide complexes 218–220 for amino acid recognition.
Figure 158: Nonactin (221), valinomycin (222) and vancomycin (223).
Figure 159: Monesin (224a) and a chiral analogue for enantiodiscrimination of ammonium guests (224b).
Figure 160: Chiral podands (226) compared to pentaglyme-dimethylether (225) and 18-crown-6 (4).
Figure 161: Lasalocid A (228).
Figure 162: Lasalocid derivatives (230) of Sessler et al.
Figure 163: The Coporphyrin I tetraanion (231).
Figure 164: Linear and cyclic peptides for ammonium ion recognition.
Figure 165: Cyclic and bicyclic depsipeptides for ammonium ion recognition.
Figure 166: α-Cyclodextrin (136a) and novocaine (236).
Figure 167: Helical diol receptor 237 by Reetz and Sostmann.
Figure 168: Ammonium binding spherand by Cram et al. (238a) and the cyclic[6]metaphenylacetylene 238b in compar...
Figure 169: Receptor for peptide backbone and ammonium binding (239).
Figure 170: Anion sensor principle with 3-hydroxy-2-naphthanilide of Jiang et al.
Figure 171: 7-bromo-3-hydroxy-N-(2-hydroxyphenyl)naphthalene 2-carboxamide (241) and its amine binding.
Figure 172: Naturally occurring catechins with affinity to quaternary ammonium ions.
Figure 173: Spiropyran (244) and merocyanine form (244a) of the amino acid receptors of Fuji et al.
Figure 174: Coumarin aldehyde (245) and its iminium species with amino acid bound (245a) by Glass et al.
Figure 175: Coumarin aldehyde appended with boronic acid.
Figure 176: Quinolone aldehyde dimers by Glass et al.
Figure 177: Chromogenic ammonium ion receptors with trifluoroacetophenone recognition motifs.
Figure 178: Chromogenic ammonium ion receptor with trifluoroacetophenone recognition motif bound on different m...
Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry
- Jiří Kulhánek,
- Filip Bureš and
- Miroslav Ludwig
Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11
- moieties is usually accomplished by cross-coupling reactions, in particular by the Suzuki–Miyaura [26][27] or the Sonogashira [28] reactions. Consequently, the availability of the suitably substituted π-conjugated linkers of various lengths bearing boronic ester functionality or terminal acetylene is
Graphical Abstract
Figure 1: Basic and newly proposed π-conjugated linkers designed for the Suzuki–Miyaura and Sonogashira cross...
Scheme 1: Convenient synthetic methods leading to π-linkers 3–6.
Scheme 2: Sonogashira cross-coupling leading to π-linkers 7c–9c.
