Search for "leaving group" in Full Text gives 251 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188
Graphical Abstract
Scheme 1: Difunctionalization of double C=C bond with the formation of C–O and C–I bonds.
Scheme 2: Iodo-oxyimidation of styrenes 1a–k with preparation of products 3aa–ka, 3ab–db, 3fb, 3hb, and 3kb.
Figure 1: Scope of the iodo-oxyimidation of vinylarenes with I2/PhI(OAc)2 system. Reaction conditions: vinyla...
Figure 2: Molecular structure of 3ca. Atoms are presented as anisotropic displacement parameters (ADP) ellips...
Scheme 3: The proposed mechanism of iodo-oxyimidation of styrene (1a) using the NHPI/I2/PhI(OAc)2 system with...
Figure 3: CV curves of styrene (1a, purple), NHPI (2a, red), I2 (blue) and PhI(OAc)2 (green) in 0.1 M n-Bu4NBF...
Scheme 4: Gram-scale synthesis of compound 3aa.
Scheme 5: Synthetic utility of the iodo-oxyimides 3aa and 3ab.
Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182
Graphical Abstract
Figure 1: General structure of PHOX ligands 1 and structures of annulated glucosamine-based PHOX and PyOx lig...
Scheme 1: Preparation of 1,2-isopropylidene-protected D-fructose derivatives with different substitution patt...
Scheme 2: Activation of 7 to oxocarbenium ion 9 in the Ritter reaction.
Scheme 3: Zemplén deacetylation of 10i.
Figure 2: Molecular structure of 10j. Ellipsoids are given at the 50% probability level. Grey = carbon, red =...
Scheme 4: Benzylation of 10j to give 10b.
Scheme 5: Plausible mechanism of the Ritter reaction. For better clarity C-2 is not shown in conformers 9a an...
Scheme 6: Neighboring group participation of ester protective groups. For better clarity C-2 is not shown in ...
Scheme 7: Pd catalyzed Tsuji–Trost reation. BSA: N,O-bis(trimethylsilyl)acetamide, DMM: dimethyl malonate.
Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177
Graphical Abstract
Figure 1: Partial structure [7,8] of the (a) graphene oxide (GO) and (b) reduced graphene oxide (RGO).
Figure 2: Mechanism of the amidation/esterification-type reactions with the GO/RGO using carbodiimide and N-h...
Figure 3: Mechanism of the Steglich esterification with the GO/RGO: (a) acid–base reaction of the carboxyl gr...
Figure 4: Mechanism of the epoxide ring opening reaction with the GO/RGO.
Figure 5: Generation of the free amine (nucleophile) from the corresponding amine hydrohalide using an acid–b...
Figure 6: Mechanism of amidation/esterification-type reactions with the GO/RGO using 1,1’-carbonyldiimidazole...
Figure 7: Mechanism of the covalent functionalization of graphene-family material applying diazonium salts ch...
Beilstein J. Org. Chem. 2018, 14, 1309–1316, doi:10.3762/bjoc.14.112
Graphical Abstract
Scheme 1: Biosynthesis of AHLs by ACP-dependent LuxI type enzymes.
Figure 1: Total ion chromatograms of the FAME extracts of A) P. inhibens 2.10, B) P. inhibens DSM17395, C) P....
Scheme 2: Synthesis of N-pantothenoylcysteamine thioesters (PCEs) for feeding experiments with AHL synthases.
Figure 2: Total ion chromatograms of the extracts from competition experiments using recombinant PgaI2 from P...
Beilstein J. Org. Chem. 2018, 14, 1287–1292, doi:10.3762/bjoc.14.110
Graphical Abstract
Scheme 1: Envisaged approach for the synthesis of 5-chloropyrazole-4-carboxylates 2.
Scheme 2: Synthesis of bipyrazolone 3a.
Figure 1: Signal of the OCH2 ester protons of reaction product 3a (500 MHz, CDCl3).
Figure 2: ORTEP-plot of the crystal structure of compound 3a drawn with 50% displacement ellipsoids [(4S,4'S)-...
Figure 3: Arrangement (4R,4'R)- and (4S,4'S)-3a enantiomers in the crystal unit drawn with 50% displacement e...
Scheme 3: Synthesis of compounds 3a–i.
Scheme 4: Reaction of different 5-hydroxypyrazoles with thionyl chloride.
Scheme 5: Reaction of 1a with sulfuryl chloride.
Scheme 6: Possible reaction mechanism for the transformation 1 → 3.
Scheme 7: Preparation of bipyrazoles 10.
Figure 4: 1H NMR (italics), 13C NMR (normal letters) and 15N NMR (in bold) chemical shifts of 3a (in CDCl3).
Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107
Graphical Abstract
Scheme 1: An overview of different chiral iodine reagents or precursors thereof.
Scheme 2: Asymmetric oxidation of sulfides by chiral hypervalent iodine reagents.
Scheme 3: Oxidative dearomatization of naphthol derivatives by Kita et al.
Scheme 4: [4 + 2] Diels–Alder dimerization reported by Birman et al.
Scheme 5: m-CPBA guided catalytic oxidative naphthol dearomatization.
Scheme 6: Oxidative dearomatization of phenolic derivatives by Ishihara et al.
Scheme 7: Oxidative spirocyclization applying precatalyst 11 developed by Ciufolini et al.
Scheme 8: Asymmetric hydroxylative dearomatization.
Scheme 9: Enantioselective oxylactonization reported by Fujita et al.
Scheme 10: Dioxytosylation of styrene (47) by Wirth et al.
Scheme 11: Oxyarylation and aminoarylation of alkenes.
Scheme 12: Asymmetric diamination of alkenes.
Scheme 13: Stereoselective oxyamination of alkenes reported by Wirth et al.
Scheme 14: Enantioselective and regioselective aminofluorination by Nevado et al.
Scheme 15: Fluorinated difunctionalization reported by Jacobsen et al.
Scheme 16: Aryl rearrangement reported by Wirth et al.
Scheme 17: α-Arylation of β-ketoesters.
Scheme 18: Asymmetric α-oxytosylation of carbonyls.
Scheme 19: Asymmetric α-oxygenation and α-amination of carbonyls reported by Wirth et al.
Scheme 20: Asymmetric α-functionalization of ketophenols using chiral quaternary ammonium (hypo)iodite salt re...
Scheme 21: Oxidative Intramolecular coupling by Gong et al.
Scheme 22: α-Sulfonyl and α-phosphoryl oxylation of ketones reported by Masson et al.
Scheme 23: α-Fluorination of β-keto esters.
Scheme 24: Alkynylation of β-ketoesters and amides catalyzed by phase-transfer catalyst.
Scheme 25: Alkynylation of β-ketoesters and dearomative alkynylation of phenols.
Beilstein J. Org. Chem. 2018, 14, 1203–1207, doi:10.3762/bjoc.14.101
Graphical Abstract
Scheme 1: Mechanistic hypothesis.
Scheme 2: Extension of the method.
Scheme 3: Carbon-based nucleophiles.
Scheme 4: THF ring opening.
Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98
Graphical Abstract
Scheme 1: Tropone (1), tropolone (2) and their resonance structures.
Figure 1: Natural products containing a tropone nucleus.
Figure 2: Possible isomers 11–13 of benzotropone.
Scheme 2: Synthesis of benzotropones 11 and 12.
Scheme 3: Oxidation products of benzotropylium fluoroborate (16).
Scheme 4: Oxidation of 7-bromo-5H-benzo[7]annulene (22).
Scheme 5: Synthesis of 4,5-benzotropone (11) using o-phthalaldehyde (27).
Scheme 6: Synthesis of 4,5-benzotropone (11) starting from oxobenzonorbornadiene 31.
Scheme 7: Acid-catalyzed cleavage of oxo-bridge of 34.
Scheme 8: Synthesis of 4,5-benzotropone (11) from o-xylylene dibromide (38).
Scheme 9: Synthesis of 4,5-benzotropone (11) via the carbene adduct 41.
Scheme 10: Heck coupling strategy for the synthesis of 11.
Scheme 11: Synthesis of benzofulvalenes via carbonyl group of 4,5-benzotropone (11).
Figure 3: Some cycloheptatrienylium cations.
Scheme 12: Synthesis of condensation product 63 and its subsequent oxidative cyclization products.
Figure 4: A novel series of benzo[7]annulenes prepared from 4,5-benzotropone (11).
Scheme 13: Preparation of substituted benzo[7]annulene 72 using the Mukaiyama-Michael reaction.
Figure 5: Possible benzo[7]annulenylidenes 73–75.
Scheme 14: Thermal and photochemical decomposition of 7-diazo-7H-benzo[7]annulene (76) and the trapping of int...
Scheme 15: Synthesis of benzoheptafulvalene 86.
Scheme 16: Synthesis of 7-(diphenylmethylene)-7H-benzo[7]annulene (89).
Scheme 17: Reaction of 4,5-benzotropone (11) with dimethyl diazomethane.
Scheme 18: Synthesis of dihydrobenzomethoxyazocine 103.
Scheme 19: Synthesis and reducibility of benzo-homo-2-methoxyazocines.
Scheme 20: Synthesis of 4,5-benzohomotropones 104 and 115 from 4,5-benzotropones 11 and 113.
Scheme 21: A catalytic deuterogenation of 4,5-benzotropone (11) and synthesis of 5-monosubstituted benzo[7]ann...
Scheme 22: Synthesis of methyl benzo[7]annulenes 131 and 132.
Scheme 23: Ambident reactivity of halobenzo[7]annulenylium cations 133a/b.
Scheme 24: Preparation of benzo[7]annulenylidene–iron complexes 147.
Scheme 25: Synthesis of 1-ethynylbenzotropone (150) and the etheric compound 152 from 4,5-benzotropone (11) wi...
Scheme 26: Thermal decomposition of 4,5-benzotropone (11).
Scheme 27: Reaction of 4,5-benzotropone (11) with 1,2-ethanediol and 1,2-ethanedithiol.
Scheme 28: Conversions of 1-benzosuberone (162) to 2,3-benzotropone (12).
Scheme 29: Synthesis strategies for 2,3-bezotropone (12) using 1-benzosuberones.
Scheme 30: Oxidation-based synthesis of 2,3-benzotropone (12) via 1-benzosuberone (162).
Scheme 31: Synthesis of 2,3-benzotropone (12) from α-tetralone (171) via ring-expansion.
Scheme 32: Preparation of 2,3-benzotropone (12) by using of benzotropolone 174.
Figure 6: Benzoheptafulvenes as condensation products of 2,3-benzotropone (12).
Scheme 33: Conversion of 2,3-benzotropone (12) to tosylhydrazone salt 182 and gem-dichloride 187.
Figure 7: Benzohomoazocines 191–193 and benzoazocines 194–197.
Scheme 34: From 2,3-benzotropone (12) to carbonium ions 198–201.
Scheme 35: Cycloaddition reactions of 2,3-benzotropone (12).
Scheme 36: Reaction of 2,3-benzotropone (12) with various reagents and compounds.
Figure 8: 3,4-Benzotropone (13) and its resonance structure.
Scheme 37: Synthesis of 6,7-benzobicyclo[3.2.0]hepta-3,6-dien-2-one (230).
Figure 9: Photolysis and thermolysis products of 230.
Figure 10: Benzotropolones and their tautomeric structures.
Scheme 38: Synthesis strategies of 4,5-benzotropolone (238).
Scheme 39: Synthesis protocol for 2-hydroxy-4,5-benzotropone (238) using oxazole-benzo[7]annulene 247.
Figure 11: Some quinoxaline and pyrazine derivatives 254–256 prepared from 4,5-benzotropolone (238).
Scheme 40: Nitration product of 4,5-benzotropolone (238) and its isomerization to 1-nitro-naphthoic acid (259)....
Scheme 41: Synthesis protocol for 6-hydroxy-2,3-benzotropone (239) from benzosuberone (162).
Scheme 42: Various reactions via 6-hydroxy-2,3-benzotropone (239).
Scheme 43: Photoreaction of 6-hydroxy-2,3-benzotropone (239).
Scheme 44: Synthesis of 7-hydroxy-2,3-benzotropone (241) from benzosuberone (162).
Scheme 45: Synthesis strategy for 7-hydroxy-2,3-benzotropone (241) from ketone 276.
Scheme 46: Synthesis of 7-hydroxy-2,3-benzotropone (241) from β-naphthoquinone (280).
Scheme 47: Synthesis of 7-hydroxy-2,3-benzotropone (241) from bicyclic endoperoxide 213.
Scheme 48: Synthesis of 7-hydroxy-2,3-benzotropone (241) by ring-closing metathesis.
Figure 12: Various monosubstitution products 289–291 of 7-hydroxy-2,3-benzotropone (241).
Scheme 49: Reaction of 7-hydroxy-2,3-benzotropone (241) with various reagents.
Scheme 50: Synthesis of 4-hydroxy-2,3-benzotropones 174 and 304 from diketones 300/301.
Scheme 51: Catalytic hydrogenation of diketones 300 and 174.
Scheme 52: Synthesis of halo-benzotropones from alkoxy-naphthalenes 306, 307 and 310.
Figure 13: Unexpected byproducts 313–315 during synthesis of chlorobenzotropone 309.
Figure 14: Some halobenzotropones and their cycloadducts.
Scheme 53: Multisep synthesis of 2-chlorobenzotropone 309.
Scheme 54: A multistep synthesis of 2-bromo-benzotropone 26.
Scheme 55: A multistep synthesis of bromo-2,3-benzotropones 311 and 316.
Scheme 56: Oxidation reactions of 8-bromo-5H-benzo[7]annulene (329) with some oxidants.
Scheme 57: Synthesis of 2-bromo-4,5-benzotropone (26).
Scheme 58: Synthesis of 6-chloro-2,3-benzotropone (335) using LiCl and proposed intermediate 336.
Scheme 59: Reaction of 7-bromo-2,3-benzotropone (316) with methylamine.
Scheme 60: Reactions of bromo-2,3-benzotropones 26 and 311 with dimethylamine.
Scheme 61: Reactions of bromobenzotropones 311 and 26 with NaOMe.
Scheme 62: Reactions of bromobenzotropones 26 and 312 with t-BuOK in the presence of DPIBF.
Scheme 63: Cobalt-catalyzed reductive cross-couplings of 7-bromo-2,3-benzotropone (316) with cyclic α-bromo en...
Figure 15: Cycloadduct 357 and its di-π-methane rearrangement product 358.
Scheme 64: Catalytic hydrogenation of 2-chloro-4,5-benzotropone (311).
Scheme 65: Synthesis of dibromo-benzotropones from benzotropones.
Scheme 66: Bromination/dehydrobromination of benzosuberone (162).
Scheme 67: Some transformations of isomeric dibromo-benzotropones 261A/B.
Scheme 68: Transformations of benzotropolone 239B to halobenzotropolones 369–371.
Figure 16: Bromobenzotropolones 372–376 and 290 prepared via bromination/dehydrobromination strategy.
Scheme 69: Synthesis of some halobenzotropolones 289, 377 and 378.
Figure 17: Bromo-chloro-derivatives 379–381 prepared via chlorination.
Scheme 70: Synthesis of 7-iodo-3,4-benzotropolone (382).
Scheme 71: Hydrogenation of bromobenzotropolones 369 and 370.
Scheme 72: Debromination reactions of mono- and dibromides 290 and 375.
Figure 18: Nitratation and oxidation products of some halobenzotropolenes.
Scheme 73: Azo-coupling reactions of some halobenzotropolones 294, 375 and 378.
Figure 19: Four possible isomers of dibenzotropones 396–399.
Figure 20: Resonance structures of tribenzotropone (400).
Scheme 74: Two synthetic pathways for tribenzotropone (400).
Scheme 75: Synthesis of tribenzotropone (400) from dibenzotropone 399.
Scheme 76: Synthesis of tribenzotropone (400) from 9,10-phenanthraquinone (406).
Scheme 77: Synthesis of tribenzotropone (400) from trifluoromethyl-substituted arene 411.
Figure 21: Dibenzosuberone (414).
Figure 22: Reduction products 415 and 416 of tribenzotropone (400).
Figure 23: Structures of tribenzotropone dimethyl ketal 417 and 4-phenylfluorenone (412) and proposed intermed...
Figure 24: Structures of benzylidene- and methylene-9H-tribenzo[a,c,e][7]annulenes 419 and 420 and chiral phos...
Figure 25: Structures of tetracyclic alcohol 422, p-quinone methide 423 and cation 424.
Figure 26: Structures of host molecules 425–427.
Scheme 78: Synthesis of non-helical overcrowded derivatives syn/anti-431.
Figure 27: Hexabenzooctalene 432.
Figure 28: Structures of possible eight isomers 433–440 of naphthotropone.
Scheme 79: Synthesis of naphthotropone 437 starting from 1-phenylcycloheptene (441).
Scheme 80: Synthesis of 10-hydroxy-11H-cyclohepta[a]naphthalen-11-one (448) from diester 445.
Scheme 81: Synthesis of naphthotropone 433.
Scheme 82: Synthesis of naphthotropones 433 and 434 via cycloaddition reaction.
Scheme 83: Synthesis of naphthotropone 434 starting from 452.
Figure 29: Structures of tricarbonyl(tropone)irons 458, and possible cycloadducts 459.
Scheme 84: Synthesis of naphthotropone 436.
Scheme 85: Synthesis of precursor 465 for naphthotropone 435.
Scheme 86: Generation of naphthotropone 435 from 465.
Figure 30: Structures of tropylium cations 469 and 470.
Figure 31: Structures of tropylium ions 471+.BF4−, 472+.BF4−, and 473+.BF4−.
Scheme 87: Synthesis of tropylium ions 471+.BF4− and 479+.ClO4−.
Scheme 88: Synthesis of 1- and 2-methylanthracene (481 and 482) via carbene–carbene rearrangement.
Figure 32: Trapping products 488–490.
Scheme 89: Generation and chemistry of a naphthoannelated cycloheptatrienylidene-cycloheptatetraene intermedia...
Scheme 90: Proposed intermediates and reaction pathways for adduct 498.
Scheme 91: Exited-state intramolecular proton transfer of 505.
Figure 33: Benzoditropones 506 and 507.
Scheme 92: Synthesis of benzoditropone 506e.
Scheme 93: Synthetic approaches for dibenzotropone 507 via tropone (1).
Scheme 94: Formation mechanisms of benzoditropone 507 and 516 via 515.
Scheme 95: Synthesis of benzoditropones 525 and 526 from pyromellitic dianhydride (527).
Figure 34: Possible three benzocyclobutatropones 534–536.
Scheme 96: Synthesis of benzocyclobutatropones 534 and 539.
Scheme 97: Synthesis attempts for benzocyclobutatropone 545.
Scheme 98: Generation and trapping of symmetric benzocyclobutatropone 536.
Scheme 99: Synthesis of chloro-benzocyclobutatropone 552 and proposed mechanism of fluorenone derivatives.
Scheme 100: Synthesis of tropolone analogue 559.
Scheme 101: Synthesis of tropolones 561 and 562.
Figure 35: o/p-Tropoquinone rings (563 and 564) and benzotropoquinones (565–567).
Scheme 102: Synthesis of benzotropoquinone 566.
Scheme 103: Synthesis of benzotropoquinone 567 via a Diels–Alder reaction.
Figure 36: Products 575–577 through 1,2,3-benzotropoquinone hydrate 569.
Scheme 104: Structures 578–582 prepared from tropoquinone 567.
Figure 37: Two possible structures 583 and 584 for dibenzotropoquinone, and precursor compound 585 for 583.
Scheme 105: Synthesis of saddle-shaped ketone 592 using dibenzotropoquinone 584.
Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68
Graphical Abstract
Figure 1: Enzymatic cleavage of phosphodiester linkages of DNA and RNA.
Figure 2: Energy profiles for a concerted ANDN (A) and stepwise mechanisms (AN + DN) with rate-limiting break...
Figure 3: Pseudorotation of a trigonal bipyramidal phosphorane intermediate by Berry pseudorotation [20].
Figure 4: Protolytic equilibria of phosphorane intermediate of RNA transesterification.
Figure 5: Structures of acyclic analogs of ribonucleosides.
Figure 6: First-order rate constants for buffer-independent partial reactions of uridyl-3´,5´-uridine at pH 5...
Scheme 1: pH- and buffer-independent cleavage and isomerization of RNA phosphodiester linkages. Observed firs...
Scheme 2: Mechanism for the pH- and buffer-independent cleavage of RNA phosphodiester linkages.
Scheme 3: Hydroxide-ion-catalyzed cleavage of RNA phosphodiester linkages.
Scheme 4: Anslyn's and Breslow's mechanism for the buffer-catalyzed cleavage and isomerization of RNA phospho...
Scheme 5: General base-catalyzed cleavage of RNA phosphodiester bonds.
Scheme 6: Kirby´s mechanism for the buffer-catalyzed cleavage of RNA phosphodiester bonds [65].
Figure 7: Guanidinium-group-based cleaving agents of RNA.
Scheme 7: Tautomers of triazine-based cleaving agents and cleavage of RNA phosphodiester bonds by these agent...
Figure 8: Bifunctional guanidine/guanidinium group-based cleaving agents of RNA.
Scheme 8: Cleavage of HPNP by 1,3-distal calix[4]arene bearing two guanidine groups [80].
Figure 9: Cyclic amine-based cleaving agents of RNA.
Scheme 9: Mechanism for the pH-independent cleavage and isomerization of model compound 12a in the pH-range 7...
Scheme 10: Mechanism for the pH-independent cleavage of guanylyl-3´,3´-(2´-amino-2´-deoxyuridine) at pH 6-8 [89].
Scheme 11: Cleavage of uridine 3´-dimethyl phosphate by A) intermolecular attack of methoxide ion and B) intra...
Scheme 12: Transesterification of group I introns and hydrolysis of phosphotriester models proceed through a s...
Scheme 13: Cleavage of trinucleoside 3´,3´,5´-monophosphates by A) P–O3´ and B) P–O5´ bond fission.
Figure 10: Model compounds (23–25) and metal ion binding ligands used in kinetic studies of metal-ion-promoted...
Figure 11: Zn2+-ion-based mono- and di-nuclear cleaving agents of nucleic acids.
Figure 12: Miscellaneous complexes and ligands used in kinetic studies of metal-ion-promoted cleavage of nucle...
Figure 13: Azacrown ligands 34 and 35 and dinuclear Zn2+ complex 36 used in kinetic studies of metal-ion-promo...
Figure 14: Metal ion complexes used for determination of βlg values of metal-ion-promoted cleavage of RNA mode...
Figure 15: Metal ion complexes used in kinetic studies of medium effects on the cleavage of RNA model compound...
Scheme 14: Alternative mechanisms for metal-ion-promoted cleavage of phosphodiesters.
Figure 16: Nucleic acid cleaving agents where the attacking oxyanion is not coordinated to metal ion.
Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65
Graphical Abstract
Figure 1: Structural components of nucleic acids. Shown is the monomeric building block of nucleic acids. Cha...
Figure 2: Formation of oxocarbenium ion during glycosidic bond cleavage in nucleosides [31]. The extent of leavin...
Figure 3: Structural modifications to nucleobase-sugar connectivity. The O–C–N bond between nucleobase and su...
Figure 4: Examples of natural and synthetic C-nucleosides. Pseudouridine and formcycin are among several natu...
Figure 5: Synthetic approaches to C-nucleosides. A. Two common strategies for C-nucleoside synthesis involve ...
Figure 6: Steroselective C-nucleoside synthesis using D-ribonolactone. A. Nucleophilic substitution of D-ribo...
Figure 7: Synthesis of C1'-substituted 4-aza-7,9-dideazaadenine C-nucleosides [63-65,69,70]. A. Reaction of D-ribonolacton...
Figure 8: Pyrrolo- and imidazo[2,1-f][1,2,4]triazine C-nucleosides. A series of sugar- and nucleobase-substit...
Figure 9: Synthesis of 1',2'-cyclopentyl C-nucleoside [73]. Functional groups at C1' and C2' were installed and e...
Figure 10: Anti-influenza C-nucleosides mimicking favipiravir riboside [74]. A. Structure of favipiravir and its r...
Figure 11: Alternative method for synthesis of 2'-substituted C-nucleosides [75]. A. Synthesis of C2'-substituted ...
Figure 12: Synthesis of carbocyclic C-nucleosides using cyclopentanone [53]. A. Nucleophlic substitution on cyclop...
Figure 13: Synthesis of carbocyclic C-nucleosides via Suzuki coupling [53]. A. Synthesis of OTf-cyclopentene that ...
Beilstein J. Org. Chem. 2018, 14, 626–633, doi:10.3762/bjoc.14.49
Graphical Abstract
Figure 1: Triazolobenzodiazepine drugs.
Scheme 1: Retrosynthetic analysis towards 2,5-diketopiperazine fused triazolobenzodiazepine.
Scheme 2: Ugi 4-CR reaction.
Scheme 3: Synthesis of diketopiperazine-fused triazolobenzodiazepine 7a.
Figure 2: Generality in the synthesis of diketopiperazine-fused triazolobenzodiazepine 7. Reaction conditions...
Scheme 4: ‘One-pot’ synthesis of diketopiperazine-fused triazolobenzodiazepines 7a and 7b.
Scheme 5: Synthesis of hydantoin-fused triazolobenzodiazepine 10. Reaction conditions: 1. 2-azidobenzaldehyde ...
Figure 3: X-ray crystal structure of hydantoin-fused triazolobenzodiazepine 10a. (Displacement ellipsoids are...
Scheme 6: Mechanism of formation of diketopiperazine and hydantoin-fused triazolobenzodiazepines.
Beilstein J. Org. Chem. 2018, 14, 603–617, doi:10.3762/bjoc.14.47
Graphical Abstract
Figure 1: Enzyme-free template-directed extension of an RNA primer by one nucleotide. B = nucleobase, LG = le...
Figure 2: Oligomerization of the 2-methylimidazolide of guanosine-5'-monophosphate on a poly(C) template.
Figure 3: Structures of backbone linkages produced in enzyme-free primer extension reactions: the phosphorami...
Figure 4: System used for studying the template effect with all 64 possible triplets at the extension site (B...
Figure 5: Interactions attracting the incoming nucleotide to the extension site. Besides base pairing via hyd...
Figure 6: Three possible fates of activated nucleotides in aqueous buffer that result from hydrolysis, primer...
Figure 7: Steps and equilibria considered in our quantitative model of chemical primer extension [34]. The model ...
Figure 8: Binding equilibrium between mononucleotides and hairpins representing primer–template duplexes, as ...
Figure 9: Template-directed primer extension on an RNA template performed with OAt-GMP at 1.8 mM (orange), 3....
Figure 10: Copying of four nucleotides on an immobilized RNA duplex, as reported by Deck et al. [32].
Figure 11: Extension cycle of aminoterminal primer with N-protected nucleotides on solid support, as described...
Figure 12: Formation of a highly reactive methylimidazolium bisphosphate from methylimidazolides of nucleotide...
Figure 13: 31P NMR spectrum (161.9 MHz) of crude MeIm-GMP in D2O. The resonance of the imidazolium bisphosphat...
Figure 14: Imidazolium bisphosphate as intermediate in the primer extension reaction, as described by Szostak ...
Figure 15: Proposed steps of enzyme-free primer extension with in situ activation, using the "general condensa...
Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30
Graphical Abstract
Scheme 1: The first ENGase-catalysed glycosylation of a GlcNAc acceptor using an N-glycan oxazoline as donor.
Scheme 2: Production of N-glycan oxazolines from peracetylated sugars using Lewis acids.
Scheme 3: Direct conversion of unprotected GlcNAc to a glycosyl oxazoline by treatment with DMC and Et3N in w...
Scheme 4: Total synthesis of a truncated complex biantennary N-glycan oxazoline via an epimerisation approach...
Scheme 5: Wangs’s total synthesis of an N-glycan oxazoline incorporating click handles, employing Crich direc...
Scheme 6: Wangs’s total synthesis of an N-glycan dodecasaccharide oxazoline employing final step oxazoline fo...
Scheme 7: Production of a phosphorylated N-glycan oxazoline, employing final step oxazoline formation with DM...
Scheme 8: Enzymatic degradation of locust bean gum, and chemical conversion into an N-glycan dodecasaccharide...
Scheme 9: Production of a complex biantennary N-glycan oxazoline from hens’ eggs by semi-synthesis via isolat...
Scheme 10: Production of a high mannose (Man-9) N-glycan oxazoline from soy bean flour.
Scheme 11: Production of a triantennary N-glycan oxazoline from bovine feruin by semi-synthesis.
Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7
Graphical Abstract
Figure 1: a) Angles and unit vectors used to define the relative orientations of the donor and acceptor trans...
Figure 2: Notable recent examples of fluorescent base analogues. For cnA and dnA the attachment point to the ...
Scheme 1: Synthesis of the tricyclic cytosine aromatic core [39]. (a) Ethylene glycol, K2CO3, 120 °C, 1 h, 40%; (...
Scheme 2: Synthesis of protected tC and tCO deoxyribose phosphonates [41]. (a) Ac2O, pyridine, rt; (b) 2-mesityle...
Scheme 3: Synthesis of protected tCnitro deoxyribose phosphoramidite [14]. a) aq NaOH, 24 h, reflux; b) EtOH, HCl...
Scheme 4: Improved synthesis of tC and tC derivatives, where R = H, 7-MeO or 8-MeO [47]. a) H2NNH2 followed by H2O...
Scheme 5: Improved synthesis of tCO derivatives [47]. a) Ac2O, pyridine, 16 h, rt, 85%; b) PPh3, CCl4, DCM, 5 h, ...
Scheme 6: Synthesis of protected tCO ribose phosphoramidite [50]. a) MesSO2Cl, DIPEA, MeCN, 4 h, rt; b) 2-aminoph...
Scheme 7: Synthesis of protected deoxyribose qA [51]. a) N-(tert-Butoxycarbonyl)-2-(trimethylstannyl)aniline, (Ph3...
Scheme 8: Synthesis of protected deoxyribose qA for DNA SPS [53]. a) AcCl, MeOH, rt, 40 min; b) p-toluoyl chlorid...
Scheme 9: Synthesis of qA derivatives. a) EtI, Cs2CO3, DMF, 4 h, rt, 90%; b) HBPin, Pd(PPh3)4, Et3N, 1,4-diox...
Scheme 10: Synthesis of quadracyclic adenine base–base FRET pair. a) HCHO, NaOH, MeCN, H2O, 50 °C, 1 h; b) TBD...
Figure 3: Absorption and emission of tC (dashed line) and tCO (solid line) in dsDNA. The absorption below 300...
Figure 4: Spectral overlap between the emission of qAN1 (cyan) and the absorption of qAnitro (black) in dsDNA...
Figure 5: Example of typical FRET efficiency as a function of number of base pairs separating the donor and a...
Figure 6: FRET efficiency as a function of number of base pairs separating the donor (qAN1) and acceptor (qAn...
Beilstein J. Org. Chem. 2018, 14, 106–113, doi:10.3762/bjoc.14.6
Graphical Abstract
Figure 1: C–F activation of benzylic fluorides to generate benzylamine or diarylmethane products.
Figure 2: 7-[2H1]-(R)-Benzyl fluoride ((R)-1).
Scheme 1: Synthesis of enantioenriched 7-[2H1]-(R)-benzyl fluoride ((R)-1) from benzaldehyde (2).
Figure 3: Partial 2H{1H} NMR (107.5 MHz) with PBLG in CHCl3 (13% w/w). (A) racemic sample of 6 (from Table 1, entry ...
Scheme 2: Synthesis of enantioenriched (S)-diarylmethane 10 from diaryl ketone 11 and confirmation of configu...
Figure 4: Possible reactive intermediates for C–F activation of benzyl fluoride 1 with strong hydrogen bond d...
Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274
Graphical Abstract
Figure 1: Schematic representation of enzymatic 5′-cap formation in eukaryotic mRNA. The 5′-triphosphate-end ...
Figure 2: Nucleotide analogues 1–11 were converted by Paramecium bursaria Chlorella virus-1 capping enzyme in...
Figure 3: Schematic representation of co-transcriptional capping with different cap analogues. A DNA-dependen...
Figure 4: (A) Structures of commercially available mRNA cap analogues. (B) Synthetic route to cap analogues a...
Figure 5: Enzymatic modification of cap analogues at their N2- or N7-position or a combination of both. (A) F...
Figure 6: Synthesis of cap-containing RNA by solid-phase synthesis. (A) A TMG-capped mRNA was synthesized sta...
Figure 7: Click chemistry for the preparation of capped RNA and cap analogues. (A) Preparation of capped RNA ...
Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273
Graphical Abstract
Scheme 1: Trifluoromethylation of silyl enol ethers.
Scheme 2: Continuous flow trifluoromethylation of ketones under photoredox catalysis.
Scheme 3: Trifluoromethylation of enol acetates.
Scheme 4: Photoredox-catalysed tandem trifluoromethylation/cyclisation of N-arylacrylamides: a route to trifl...
Scheme 5: Tandem trifluoromethylation/cyclisation of N-arylacrylamides using BiOBr nanosheets catalysis.
Scheme 6: Photoredox-catalysed trifluoromethylation/desulfonylation/cyclisation of N-tosyl acrylamides (bpy: ...
Scheme 7: Photoredox-catalysed trifluoromethylation/aryl migration/desulfonylation of N-aryl-N-tosylacrylamid...
Scheme 8: Proposed mechanism for the trifluoromethylation/aryl migration/desulfonylation (/cyclisation) of N-...
Scheme 9: Photoredox-catalysed trifluoromethylation/cyclisation of N-methacryloyl-N-methylbenzamide derivativ...
Scheme 10: Photoredox-catalysed trifluoromethylation/cyclisation of N-methylacryloyl-N-methylbenzamide derivat...
Scheme 11: Photoredox-catalysed trifluoromethylation/dearomatising spirocyclisation of a N-benzylacrylamide de...
Scheme 12: Photoredox-catalysed trifluoromethylation/cyclisation of an unactivated alkene.
Scheme 13: Asymmetric radical aminotrifluoromethylation of N-alkenylurea derivatives using a dual CuBr/chiral ...
Scheme 14: Aminotrifluoromethylation of an N-alkenylurea derivative using a dual CuBr/phosphoric acid catalyti...
Scheme 15: 1,2-Formyl- and 1,2-cyanotrifluoromethylation of alkenes under photoredox catalysis.
Scheme 16: First simultaneous introduction of the CF3 moiety and a Cl atom onto alkenes.
Scheme 17: Chlorotrifluoromethylaltion of terminal, 1,1- and 1,2-substituted alkenes.
Scheme 18: Chorotrifluoromethylation of electron-deficient alkenes (DCE = dichloroethane).
Scheme 19: Cascade trifluoromethylation/cyclisation/chlorination of N-allyl-N-(benzyloxy)methacrylamide.
Scheme 20: Cascade trifluoromethylation/cyclisation (/chlorination) of diethyl 2-allyl-2-(3-methylbut-2-en-1-y...
Scheme 21: Trifluoromethylchlorosulfonylation of allylbenzene derivatives and aliphatic alkenes.
Scheme 22: Access to β-hydroxysulfones from CF3-containing sulfonyl chlorides through a photocatalytic sequenc...
Scheme 23: Cascade trifluoromethylchlorosulfonylation/cyclisation reaction of alkenols: a route to trifluorome...
Scheme 24: First direct C–H trifluoromethylation of arenes and proposed mechanism.
Scheme 25: Direct C–H trifluoromethylation of five- and six-membered (hetero)arenes under photoredox catalysis....
Scheme 26: Alternative pathway for the C–H trifluoromethylation of (hetero)arenes under photoredox catalysis.
Scheme 27: Direct C–H trifluoromethylation of five- and six-membered ring (hetero)arenes using heterogeneous c...
Scheme 28: Trifluoromethylation of terminal olefins.
Scheme 29: Trifluoromethylation of enamides.
Scheme 30: (E)-Selective trifluoromethylation of β-nitroalkenes under photoredox catalysis.
Scheme 31: Photoredox-catalysed trifluoromethylation/cyclisation of an o-azidoarylalkynes.
Scheme 32: Regio- and stereoselective chlorotrifluoromethylation of alkynes.
Scheme 33: PMe3-mediated trifluoromethylsulfenylation by in situ generation of CF3SCl.
Scheme 34: (EtO)2P(O)H-mediated trifluoromethylsulfenylation of (hetero)arenes and thiols.
Scheme 35: PPh3/NaI-mediated trifluoromethylsulfenylation of indole derivatives.
Scheme 36: PPh3/n-Bu4NI mediated trifluoromethylsulfenylation of thiophenol derivatives.
Scheme 37: PPh3/Et3N mediated trifluoromethylsulfinylation of benzylamine.
Scheme 38: PCy3-mediated trifluoromethylsulfinylation of azaarenes, amines and phenols.
Scheme 39: Mono- and dichlorination of carbon acids.
Scheme 40: Monochlorination of (N-aryl-N-hydroxy)acylacetamides.
Scheme 41: Examples of the synthesis of heterocycles fused with β-lactams through a chlorination/cyclisation p...
Scheme 42: Enantioselective chlorination of β-ketoesters and oxindoles.
Scheme 43: Enantioselective chlorination of 3-acyloxazolidin-2-one derivatives (NMM = N-methylmorpholine).
Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272
Graphical Abstract
Scheme 1: Trifluoromethylation of enol acetates by Langlois.
Scheme 2: Trifluoromethylation of (het)aryl enol acetates.
Scheme 3: Mechanism for the trifluoromethylation of enol acetates.
Scheme 4: Oxidative trifluoromethylation of unactivated olefins and mechanistic pathway.
Scheme 5: Oxidative trifluoromethylation of acetylenic substrates.
Scheme 6: Metal free trifluoromethylation of styrenes.
Scheme 7: Synthesis of α-trifluoromethylated ketones by oxytrifluoromethylation of heteroatom-functionalised ...
Scheme 8: Catalysed photoredox trifluoromethylation of vinyl azides.
Scheme 9: Oxidative difunctionalisation of alkenyl MIDA boronates.
Scheme 10: Synthesis of β-trifluoromethyl ketones from cyclopropanols.
Scheme 11: Aryltrifluoromethylation of allylic alcohols.
Scheme 12: Cascade multicomponent synthesis of nitrogen heterocycles via azotrifluoromethylation of alkenes.
Scheme 13: Photocatalytic azotrifluoromethylation of alkenes with aryldiazonium salts and CF3SO2Na.
Scheme 14: Copper-promoted intramolecular aminotrifluoromethylation of alkenes with CF3SO2Na.
Scheme 15: Oxytrifluoromethylation of alkenes with CF3SO2Na and hydroxamic acid.
Scheme 16: Manganese-catalysed oxytrifluoromethylation of styrene derivatives.
Scheme 17: Oxytrifluoromethylation of alkenes with NMP/O2 and CF3SO2Na.
Scheme 18: Intramolecular oxytrifluoromethylation of alkenes.
Scheme 19: Hydrotrifluoromethylation of styrenyl alkenes and unactivated aliphatic alkenes.
Scheme 20: Hydrotrifluoromethylation of electron-deficient alkenes.
Scheme 21: Hydrotrifluoromethylation of alkenes by iridium photoredox catalysis.
Scheme 22: Iodo- and bromotrifluoromethylation of alkenes by CF3SO2Na/I2O5 or CF3SO2Na / NaBrO3.
Scheme 23: N-methyl-9-mesityl acridinium and visible-light-induced chloro-, bromo- and SCF3 trifluoromethylati...
Scheme 24: Carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na / TBHP by Lipshutz.
Scheme 25: Carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/TBHP reported by Lei.
Scheme 26: Carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/(NH4)2S2O8.
Scheme 27: Metal-free carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/K2S2O8 reported by Wang.
Scheme 28: Metal-free carbotrifluoromethylation of N-arylacrylamides with CF3SO2Na/PIDA reported by Fu.
Scheme 29: Metal-free cascade trifluoromethylation/cyclisation of N-arylmethacrylamides (a) and enynes (b) wit...
Scheme 30: Trifluoromethylation/cyclisation of N-arylcinnamamides: Synthesis of 3,4-disubstituted dihydroquino...
Scheme 31: Trifluoromethylation/cyclisation of aromatic-containing unsaturated ketones.
Scheme 32: Chemo- and regioselective cascade trifluoromethylation/heteroaryl ipso-migration of unactivated alk...
Scheme 33: Copper-mediated 1,2-bis(trifluoromethylation) of alkenes.
Scheme 34: Trifluoromethylation of aromatics with CF3SO2Na reported by Langlois.
Scheme 35: Baran’s oxidative C–H trifluoromethylation of heterocycles.
Scheme 36: Trifluoromethylation of acetanilides and anilines.
Scheme 37: Trifluoromethylation of heterocycles in water.
Scheme 38: Trifluoromethylation of coumarins in a continuous-flow reactor.
Scheme 39: Oxidative trifluoromethylation of coumarins, quinolines and pyrimidinones.
Scheme 40: Oxidative trifluoromethylation of pyrimidinones and pyridinones.
Scheme 41: Phosphovanadomolybdic acid-catalysed direct C−H trifluoromethylation.
Scheme 42: Oxidative trifluoromethylation of imidazopyridines and imidazoheterocycles.
Scheme 43: Oxidative trifluoromethylation of imidazoheterocycles and imidazoles in ionic liquid/water.
Scheme 44: Oxidative trifluoromethylation of 8-aminoquinolines.
Scheme 45: Oxidative trifluoromethylation of various 8-aminoquinolines using the supported catalyst CS@Cu(OAc)2...
Scheme 46: Oxidative trifluoromethylation of the naphthylamide 70.
Scheme 47: Oxidative trifluoromethylation of various arenes in the presence of CF3SO2Na and sodium persulfate.
Scheme 48: Trifluoromethylation of electron-rich arenes and unsymmetrical biaryls with CF3SO2Na in the presenc...
Figure 1: Trifluoromethylated coumarin and flavone.
Scheme 49: Metal-free trifluoromethylation catalysed by a photoredox organocatalyst.
Scheme 50: Quinone-mediated trifluoromethylation of arenes and heteroarenes.
Scheme 51: Metal- and oxidant-free photochemical trifluoromethylation of arenes.
Scheme 52: Copper-mediated trifluoromethylation of arenediazonium tetrafluoroborates.
Scheme 53: Oxidative trifluoromethylation of aryl- and heteroarylboronic acids.
Scheme 54: Oxidative trifluoromethylation of aryl- and vinylboronic acids.
Scheme 55: Oxidative trifluoromethylation of unsaturated potassium organotrifluoroborates.
Scheme 56: Oxidative trifluoromethylation of (hetero)aryl- and vinyltrifluoroborates.
Scheme 57: Copper−catalysed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 58: Iron-mediated decarboxylative trifluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 59: Cu/Ag-catalysed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 60: I2O5-Promoted decarboxylative trifluoromethylation of cinnamic acids.
Scheme 61: Silver(I)-catalysed denitrative trifluoromethylation of β-nitrostyrenes.
Scheme 62: Copper-catalysed direct trifluoromethylation of styrene derivatives.
Scheme 63: Transition-metal-free synthesis of β-trifluoromethylated enamines.
Scheme 64: I2O5-mediated iodotrifluoromethylation of alkynes.
Scheme 65: Silver-catalysed tandem trifluoromethylation/cyclisation of aryl isonitriles.
Scheme 66: Photoredox trifluoromethylation of 2-isocyanobiphenyls.
Scheme 67: Trifluoromethylation of potassium alkynyltrifluoroborates with CF3SO2Na.
Scheme 68: N-trifluoromethylation of nitrosoarenes with CF3SO2Na (SQ: semiquinone).
Scheme 69: Trifluoromethylation of disulfides with CF3SO2Na.
Scheme 70: Trifluoromethylation of thiols with CF3SO2Na/I2O5.
Scheme 71: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/(EtO)2P(O)H/CuCl/DMSO.
Scheme 72: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/(EtO)2P(O)H/TMSCl.
Scheme 73: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/PPh3/N-chlorophthalimide.
Scheme 74: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/PCl3.
Scheme 75: Electrophilic trifluoromethylsulfenylation by means of CF3SO2Na/PCl3.
Scheme 76: Trifluoromethylsulfenylation of aryl iodides with in situ generated CuSCF3 (DMI: 1,3-dimethyl-2-imi...
Scheme 77: Pioneering trifluoromethylsulfinylation of N, O, and C-nucleophiles.
Scheme 78: Trifluoromethylsulfinylation of (1R,2S)-ephedrine (Im: imidazole; DIEA: N,N-diisopropylethylamine).
Scheme 79: Trifluoromethylsulfinylation of substituted benzenes with CF3SO2Na/CF3SO3H.
Scheme 80: Trifluoromethylsulfinylation of indoles with CF3SO2Na/P(O)Cl3.
Scheme 81: Trifluoromethylsulfinylation of indoles with CF3SO2Na/PCl3.
Scheme 82: Formation of triflones from benzyl bromides (DMA: dimethylacetamide).
Scheme 83: Formation of α-trifluoromethylsulfonyl ketones, esters, and amides.
Scheme 84: Allylic trifluoromethanesulfonylation of aromatic allylic alcohols.
Scheme 85: Copper-catalysed couplings of aryl iodonium salts with CF3SO2Na.
Scheme 86: Palladium-catalysed trifluoromethanesulfonylation of aryl triflates and chlorides with CF3SO2Na.
Scheme 87: Copper-catalysed coupling of arenediazonium tetrafluoroborates with CF3SO2Na.
Scheme 88: Synthesis of phenyltriflone via coupling of benzyne with CF3SO2Na.
Scheme 89: Synthesis of 1-trifluoromethanesulfonylcyclopentenes from 1-alkynyl-λ3-bromanes and CF3SO2Na.
Scheme 90: One-pot synthesis of functionalised vinyl triflones.
Scheme 91: Regioselective synthesis of vinyltriflones from styrenes.
Scheme 92: Trifluoromethanesulfonylation of alkynyl(phenyl) iodonium tosylates by CF3SO2Na.
Scheme 93: Synthesis of thio- and selenotrifluoromethanesulfonates.
Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270
Graphical Abstract
Scheme 1: Two different intermolecular cyclization pathways controlled by reagents used.
Scheme 2: Scope of reaction. Reaction conditions: 1 (1.2 mmol), 2 (1.0 mmol), KOt-Bu (2 mmol), in 3 mL CBrCl3...
Scheme 3: Scope of the reaction. Reaction conditions: 1 (1.0 mmol), 2 (1.5 mmol), In(OTf)3 (0.1 mmol), in 1.5...
Scheme 4: Control experiments.
Figure 1: Proposed mechanism (benzo[d]imidazo[2,1-b]thiazoles).
Figure 2: Proposed mechanism (benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones).
Beilstein J. Org. Chem. 2017, 13, 2364–2371, doi:10.3762/bjoc.13.233
Graphical Abstract
Scheme 1: Fluorination of diol derivative (±)-1.
Scheme 2: Fluorination of diol derivative (±)-4.
Figure 1: X-ray structure of fluorohydrine derivative (±)-5.
Scheme 3: Fluorination of diol derivative (±)-6.
Scheme 4: Fluorination of cyclohexane-derived diol (±)-8.
Scheme 5: Proposed route for the formation of compounds (±)-10 and (±)-11.
Scheme 6: Fluorination of diol derivative (±)-12.
Scheme 7: Fluorination of diol derivative (±)-14.
Scheme 8: Proposed route for the formation of compounds (±)-15, (±)-16 and (±)-17.
Scheme 9: Fluorination of N-Cbz-protected diol derivative (±)-18.
Scheme 10: Fluorination of diol derivative (±)-20.
Scheme 11: Fluorination of meso diol derivative 24.
Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228
Graphical Abstract
Figure 1: Examples of conformationally biased amino acids [1-10]. Compound 6 is a target of this work.
Scheme 1: The first synthetic approach.
Scheme 2: The second synthetic approach.
Scheme 3: The third synthetic approach.
Scheme 4: The fourth synthetic approach (partially reproduced from ref. [17]).
Figure 2: Selected J values and the inferred molecular conformations of 6a and 6b.
Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219
Graphical Abstract
Figure 1: Summary of the synthetic routes to prepare phosphonic acids detailed in this review. The numbers in...
Figure 2: Chemical structure of dialkyl phosphonate, phosphonic acid and illustration of the simplest phospho...
Figure 3: Illustration of some phosphonic acid exhibiting bioactive properties. A) Phosphonic acids for biome...
Figure 4: Illustration of the use of phosphonic acids for their coordination properties and their ability to ...
Figure 5: Hydrolysis of dialkyl phosphonate to phosphonic acid under acidic conditions.
Figure 6: Examples of phosphonic acids prepared by hydrolysis of dialkylphosphonate with HCl 35% at reflux (16...
Figure 7: A) and B) Observation of P–C bond breaking during the hydrolysis of phosphonate with concentrated H...
Figure 8: Mechanism of the hydrolysis of dialkyl phosphonate with HCl in water.
Figure 9: Hydrolysis of bis-tert-butyl phosphonate 28 into phosphonic acid 29 [137].
Figure 10: A) Hydrolysis of diphenyl phosphonate into phosphonic acid in acidic media. B) Examples of phosphon...
Figure 11: Suggested mechanism occurring for the first step of the hydrolysis of diphenyl phosphonate into pho...
Figure 12: A) Hydrogenolysis of dibenzyl phosphonate to phosphonic acid. B) Compounds 33, 34 and 35 were prepa...
Figure 13: A) Preparation of phosphonic acid from diphenyl phosphonate with the Adam’s catalyst. B) Compounds ...
Figure 14: Suggested mechanism for the preparation of phosphonic acid from dialkyl phosphonate using bromotrim...
Figure 15: A) Reaction of the phosphonate-thiophosphonate 37 with iodotrimethylsilane followed by methanolysis...
Figure 16: Synthesis of hydroxymethylenebisphosphonic acid by reaction of tris(trimethylsilyl) phosphite with ...
Figure 17: Synthesis of the phosphonic acid disodium salt 48 by reaction of mono-hydrolysed phosphonate 47 wit...
Figure 18: Phosphonic acid synthesized by the sequence 1) bromotrimethylsilane 2) methanolysis or hydrolysis. ...
Figure 19: Polyphosphonic acids and macromolecular compounds prepared by the hydrolysis of dialkyl phosphonate...
Figure 20: Examples of organometallic complexes functionalized with phosphonic acids that were prepared by the...
Figure 21: Side reaction observed during the hydrolysis of methacrylate monomer functionalized with phosphonic...
Figure 22: Influence of the reaction time during the hydrolysis of compound 76.
Figure 23: Dealkylation of dialkyl phosphonates with boron tribromide.
Figure 24: Dealkylation of diethylphosphonate 81 with TMS-OTf.
Figure 25: Synthesis of substituted phenylphosphonic acid 85 from the phenyldichlorophosphine 83.
Figure 26: Hydrolysis of substituted phenyldichlorophosphine oxide 86 under basic conditions.
Figure 27: A) Illustration of the synthesis of chiral phosphonic acids from phosphonodiamides. B) Examples of ...
Figure 28: A) Illustration of the synthesis of the phosphonic acid 98 from phosphonodiamide 97. B) Use of cycl...
Figure 29: Synthesis of tris(phosphonophenyl)phosphine 109.
Figure 30: Moedritzer–Irani reaction starting from A) primary amine or B) secondary amine. C) Examples of phos...
Figure 31: Phosphonic acid-functionalized polymers prepared by Moedritzer–Irani reaction.
Figure 32: Reaction of phosphorous acid with imine in the absence of solvent.
Figure 33: A) Reaction of phosphorous acid with nitrile and examples of aminomethylene bis-phosphonic acids. B...
Figure 34: Reaction of carboxylic acid with phosphorous acid and examples of compounds prepared by this way.
Figure 35: Synthesis of phosphonic acid by oxidation of phosphinic acid (also identified as phosphonous acid).
Figure 36: Selection of reaction conditions to prepare phosphonic acids from phosphinic acids.
Figure 37: Synthesis of phosphonic acid from carboxylic acid and white phosphorus.
Figure 38: Synthesis of benzylphosphonic acid 136 from benzaldehyde and red phosphorus.
Figure 39: Synthesis of graphene phosphonic acid 137 from graphite and red phosphorus.
Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207
Graphical Abstract
Scheme 1: a) Traditional glycosylation typically employs the premixed approach with both the donor and the ac...
Scheme 2: Glycosylation of an unreactive substrate. Reagents and conditions: (a) Tf2O, −78 °C, CH2Cl2 (DCM), ...
Scheme 3: Bromoglycoside-mediated glycosylation.
Scheme 4: Glycosyl bromide-mediated selenoglycosyl donor-based iterative glycosylation. Reagents and conditio...
Scheme 5: Preactivation-based glycosylation using 2-pyridyl glycosyl donors.
Scheme 6: Chemoselective dehydrative glycosylation. Reagents and conditions: (a) Ph2SO, Tf2O, 2-chloropyridin...
Figure 1: Representative structures of products formed by the preactivation-based dehydrative glycosylation o...
Scheme 7: Possible mechanism for the dehydrative glycosylation. (a) Formation of diphenyl sulfide bis(triflat...
Scheme 8: Chemoselective iterative dehydrative glycosylation. Reagents and conditions: (a) Ph2SO, Tf2O, 2,4,6...
Scheme 9: Chemoselective iterative dehydrative glycosylation. Reagents and conditions: (a) Ph2SO, Tf2O, −40 °...
Scheme 10: Chemical synthesis of a hyaluronic acid (HA) trimer 47. Reagents and conditions: (a) Ph2SO, TTBP, CH...
Figure 2: Retrosynthetic analysis of pentasaccharide 48.
Scheme 11: Effects of anomeric leaving groups on glycosylation outcomes. Reagents and conditions: (a) Ph2SO, Tf...
Scheme 12: Reactivity-based one-pot chemoselective glycosylation.
Scheme 13: Preactivation-based iterative glycosylation of thioglycosides.
Scheme 14: BSP/Tf2O promoted synthesis of 75.
Scheme 15: Proposed mechanism for preactivation-based glycosylation strategy.
Figure 3: The preactivations of glycosyl donors 83, 85 and 87 were investigated by low temperature NMR, which...
Scheme 16: The more electron-rich glycosyl donor 91 gave a higher glycosylation yield than the glycosyl donor ...
Scheme 17: Comparison of the BSP/Tf2O and p-TolSCl/AgOTf promoter systems in facilitating the preactivation-ba...
Scheme 18: One-pot synthesis of Globo-H hexasaccharide 105 using building blocks 101, 102, 103 and 104.
Scheme 19: Synthesis of (a) oligosaccharides 109–113 towards (b) 30-mer galactan 115. Reagents and conditions:...
Figure 4: Structure of mycobacterial arabinogalactan 116.
Figure 5: Representative complex glycans from glycolipid family synthesized by the preactivation-based thiogl...
Figure 6: Representative microbial and mammalian oligosaccharides synthesized by the preactivation-based thio...
Figure 7: Some representative mammalian oligosaccharides synthesized by the preactivation-based thioglycoside...
Figure 8: Preparation of a heparan sulfate oligosaccharides library.
Scheme 20: Synthesis of oligo-glucosamines through electrochemical promoted preactivation-based thioglycoside ...
Scheme 21: Synthesis of 2-deoxyglucosides through preactivation. Reagents and conditions: a) AgOTf, p-TolSCl, ...
Scheme 22: Synthesis of tetrasaccharide 153. Reagents and conditions: (a) AgOTf, p-TolSCl, CH2Cl2, −78 °C; the...
Scheme 23: Aglycon transfer from a thioglycosyl acceptor to an activated donor can occur during preactivation-...
Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201
Graphical Abstract
Scheme 1: The mechanistic outline of the intermolecular (a) and intramolecular (b) glycosylation reactions.
Figure 1: Three general concepts for intramolecular glycosylation reactions.
Scheme 2: First intramolecular glycosylation using the molecular clamping.
Scheme 3: Succinoyl as a flexible linker for intramolecular glycosylation of prearranged glycosides.
Scheme 4: Template-directed cyclo-glycosylation using a phthaloyl linker.
Scheme 5: Phthaloyl linker-mediated synthesis of branched oligosaccharides via remote glycosidation.
Scheme 6: Molecular clamping with the phthaloyl linker in the synthesis of α-cyclodextrin.
Scheme 7: m-Xylylene as a rigid tether for intramolecular glycosylation.
Scheme 8: Oligosaccharide synthesis using rigid xylylene linkers.
Scheme 9: Stereo- and regiochemical outcome of peptide-based linkers.
Scheme 10: Positioning effect of donor and acceptor in peptide templated synthesis.
Scheme 11: Synthesis of a trisaccharide using a non-symmetrical tether strategy.
Scheme 12: Effect of ring on glycosylation with a furanose.
Scheme 13: Rigid BPA template with various linkers.
Scheme 14: The templated synthesis of maltotriose in complete stereoselectivity.
Scheme 15: First examples of the IAD.
Scheme 16: Long range IAD via dimethylsilane.
Scheme 17: Allyl-mediated tethering strategy in the IAD.
Scheme 18: IAD using tethering via the 2-naphthylmethyl group.
Scheme 19: Origin of selectivity in boronic ester mediated IAD.
Scheme 20: Arylborinic acid approach to the synthesis of β-mannosides.
Figure 2: Facial selectivity during HAD.
Scheme 21: Possible mechanisms to explain α and β selectivity in palladium mediated IAD.
Scheme 22: DISAL as the leaving group that favors the intramolecular glycosylation pathway.
Scheme 23: Boronic acid as a directing group in the leaving group-based glycosylation method.
Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159
Graphical Abstract
Figure 1: Initial proposal for the core macrolactone structure (left) and the established complete structure ...
Figure 2: Mycolactone congeners and their origins.
Figure 3: Misassigned mycolactone E structure according to Small et al. [50] (11) and the correct structure (6) f...
Figure 4: Schematic illustration of Kishi’s improved mycolactone TLC detection method exploiting derivatizati...
Figure 5: Fluorescent probes derived from natural mycolactone A/B (1a,b) or its synthetic 8-desmethyl analogs...
Figure 6: Tool compounds used by Pluschke and co-workers for elucidating the molecular targets of mycolactone...
Figure 7: Synthetic strategies towards the extended mycolactone core. A) General strategies. B) Kishi’s appro...
Scheme 1: Kishi’s 1st generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 2: Kishi’s 2nd generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 3: Kishi’s 3rd generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 4: Negishi’s synthesis of the extended core structure of mycolactones. Reagents and conditions: a) (i) ...
Scheme 5: Burkart’s (incomplete) 1st generation approach towards the extended core structure of mycolactones....
Scheme 6: Burkart’s (incomplete) 1st, 2nd and 3rd generation approach towards the extended mycolactone core s...
Scheme 7: Altmann’s synthesis of alkyl iodide 91. Reagents and conditions: a) (i) PMB-trichloroacetimidate, T...
Scheme 8: Final steps of Altmann’s synthesis of the extended core structure of mycolactones. Reagents and con...
Scheme 9: Basic principles of the Aggarwal lithiation–borylation homologation process [185,186].
Scheme 10: Aggarwal’s synthesis of the C1–C11 fragment of the mycolactone core. Reagents and conditions: a) Cl...
Scheme 11: Aggarwal’s synthesis of the linear C1–C20 fragment of the mycolactone core. Reagents and conditions...
Figure 8: Synthetic strategies towards the mycolactone A/B lower side chain.
Scheme 12: Gurjar and Cherian’s synthesis of the C1’–C8’ fragment of the mycolactone A/B pentaenoate side chai...
Scheme 13: Gurjar and Cherian’s synthesis of the benzyl-protected mycolactone A/B pentaenoate side chain. Reag...
Scheme 14: Kishi’s synthesis of model compounds for elucidating the stereochemistry of the C7’–C16’ fragment o...
Scheme 15: Kishi’s synthesis of the mycolactone A/B pentaenoate side chain. (a) (i) NaH, (EtO)2P(O)CH2CO2Et, T...
Scheme 16: Feringa and Minnaard's incomplete synthesis of mycolactone A/B pentaenoate side chain. Reagents and...
Scheme 17: Altmann’s approach towards the mycolactone A/B pentaenoate side chain. Reagents and conditions: a) ...
Scheme 18: Negishi’s access to the C1’–C7’ fragment of mycolactone A. Reagents and conditions: a) (i) n-BuLi, ...
Scheme 19: Negishi’s approach to the C1’–C7’ fragment of mycolactone B. Reagents and conditions: a) (i) DIBAL-...
Scheme 20: Negishi’s synthesis of the C8’–C16’ fragment of mycolactone A/B. Reagents and conditions: a) 142, BF...
Scheme 21: Negishi’s assembly of the mycolactone A and B pentaenoate side chains. Reagents and conditions: a) ...
Scheme 22: Blanchard’s approach to the mycolactone A/B pentaenoate side chain. a) (i) Ph3P=C(Me)COOEt, CH2Cl2,...
Scheme 23: Kishi’s approach to the mycolactone C pentaenoate side chain exemplified for the 13’R,15’S-isomer 1...
Scheme 24: Altmann’s (unpublished) synthesis of the mycolactone C pentaenoate side chain. Reagents and conditi...
Scheme 25: Blanchard’s synthesis of the mycolactone C pentaenoate side chain. Reagents and conditions: a) (i) ...
Scheme 26: Kishi’s synthesis of the tetraenoate side chain of mycolactone F exemplified by enantiomer 165. Rea...
Scheme 27: Kishi’s synthesis of the mycolactone E tetraenoate side chain. Reagents and conditions: a) (i) CH2=...
Scheme 28: Wang and Dai’s synthesis of the mycolactone E tetraenoate side chain. Reagents and conditions: a) (...
Scheme 29: Kishi’s synthesis of the dithiane-protected tetraenoate side chain of the minor oxo-metabolite of m...
Scheme 30: Kishi’s synthesis of the mycolactone S1 and S2 pentaenoate side chains. Reagents and conditions: a)...
Scheme 31: Kishi’s 1st generation and Altmann’s total synthesis of mycolactone A/B (1a,b) and Negishi’s select...
Scheme 32: Kishi’s 2nd generation total synthesis of mycolactone A/B (1a,b). Reagents and conditions: a) 2,4,6...
Scheme 33: Blanchard’s synthesis of the 8-desmethylmycolactone core. Reagents and conditions: a) (i) TsCl, TEA...
Scheme 34: Altmann’s (partially unpublished) synthesis of the C20-hydroxylated mycolactone core. Reagents and ...
Scheme 35: Altmann’s and Blanchard’s approaches towards the 11-isopropyl-8-desmethylmycolactone core. Reagents...
Scheme 36: Blanchard’s synthesis of the saturated variant of the C11-isopropyl-8-desmethylmycolactone core. Re...
Scheme 37: Structure elucidation of photo-mycolactones generated from tetraenoate 224.
Scheme 38: Kishi’s synthesis of the linear precursor of the photo-mycolactone B1 lower side chain. Reagents an...
Scheme 39: Kishi’s synthesis of the photo-mycolactone B1 lower side chain. Reagents and conditions: a) LiTMP, ...
Scheme 40: Kishi’s synthesis of a stabilized lower mycolactone side chain. Reagents and conditions: a) (i) TBD...
Scheme 41: Blanchard’s variation of the C12’,C13’,C15’ stereocluster. Reagents and conditions: a) (i) DIBAL-H,...
Scheme 42: Blanchard’s synthesis of aromatic mycolactone polyenoate side chain analogs. Reagents and condition...
Scheme 43: Small’s partial synthesis of a BODIPY-labeled mycolactone derivative and Demangel’s partial synthes...
Scheme 44: Blanchard’s synthesis of the BODIPY-labeled 8-desmethylmycolactones. Reagents and conditions: a) (i...
Scheme 45: Altmann’s synthesis of biotinylated mycolactones. Reagents and conditions: a) (i) CDI, THF, rt, 2 d...
Figure 9: Kishi’s elongated n-butyl carbamoyl mycolactone A/B analog.