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Search for "pyrroles" in Full Text gives 146 result(s) in Beilstein Journal of Organic Chemistry.
Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate
- Mysore Bhyrappa Harisha,
- Pandi Dhanalakshmi,
- Rajendran Suresh,
- Raju Ranjith Kumar and
- Shanmugam Muthusubramanian
Beilstein J. Org. Chem. 2020, 16, 2108–2118, doi:10.3762/bjoc.16.178
- precursor for nitrogen heterocycles. As a part of our synthetic design towards the construction of five-membered heterocycles, we have previously reported the synthesis of highly substituted imidazoles [6], indoles [7] and pyrroles [8] starting from different azidochalcones. In continuation, employing α
Graphical Abstract
Figure 1: Examples of biologically active oxazole and aminothiazole scaffolds.
Scheme 1: Strategies for the synthesis of 2,4,5-trisubstituted oxazole from azirine. a) I2, PPh3; b) NaH, 1H-...
Scheme 2: Scope of the α-azidochalcones. The reactions were carried out at reflux temperature, using 1 (1 mmo...
Scheme 3: Large-scale synthesis of 3i.
Figure 2: Large-scale synthesis of 3i. a) At the start of the reaction, b) after the reaction.
Scheme 4: Acetyl derivative of 3d.
Figure 3: ORTEP diagram of compound 5.
Scheme 5: Synthesis of S-methyl/benzylated products 6 and 7.
Scheme 6: Control experiments.
Scheme 7: Plausible mechanism proposed for the formation of 2,4,5-trisubstituted oxazoles 3.
Scheme 8: Reaction of vinyl azide 1 and 3 with ferric nitrate. Reactions were carried out at reflux temperatu...
Figure 4: X-ray crystal structure of 4h.
Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes
- Thomas Schneider,
- Michael Keim,
- Bianca Seitz and
- Gerhard Maas
Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173
- -iminium triflates R‒C≡C‒C(CF3)=N+Me2 TfO− [27]. As a first synthetic application, we have reported the phospha-Michael addition providing 3-(triphenylphosphonio)-1-(trifluoromethyl)-1-(dimethylamino)allenes, which were subsequently transformed into α-(trifluoromethyl)pyrroles. In the present paper, we
Graphical Abstract
Scheme 1: Diels–Alder reaction of propyn-1-iminium salt 1a compared with the reported [29] reaction of 4-phenyl-1...
Scheme 2: Sequential Diels–Alder/intramolecular SE(Ar) reaction of propyn-1-iminium triflates 1a,b. Condition...
Scheme 3: Diels–Alder reaction of 1a and anthracene followed by an intramolecular SE(Ar) reaction.
Figure 1: Solid-state molecular structure of 11 (ORTEP plot).
Scheme 4: Reactions of propyn-1-iminium salt 1a with styrenes.
Figure 2: Solid-state molecular structure of 12c (ORTEP plot).
Figure 3: Solid-state molecular structure of 12d (ORTEP plot). Both the R and the S enantiomer are present in...
Scheme 5: A mechanistic proposal for the reaction of alkyne 1a with styrenes.
Scheme 6: Reaction of alkyne 1a with 1,2-dihydronaphthalene.
Scheme 7: Synthesis and solid-state molecular structure (ORTEP plot) of pentafulvene 19; selected bond distan...
Scheme 8: Proposed mechanistic pathway leading to fulvene 19.
Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides
- Vladimir P. Rybalkin,
- Sofiya Yu. Zmeeva,
- Lidiya L. Popova,
- Valerii V. Tkachev,
- Andrey N. Utenyshev,
- Olga Yu. Karlutova,
- Alexander D. Dubonosov,
- Vladimir A. Bren,
- Sergey M. Aldoshin and
- Vladimir I. Minkin
Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149
- -isomers and of products of the photoinduced rearrangement completed by 1,5-H shift reaction, 3a,4-dihydronaphtho[2,3-c]furans(pyrroles) C, were established based on the data of 1H and 13C NMR spectroscopy and X-ray diffraction studies. Keywords: benzo[b]thiophene; fulgide; fulgimide; photorearrangement
Graphical Abstract
Scheme 1: Photoisomerization of 2-benzo[b]thienyl fulgides.
Scheme 2: Synthesis of fulgides 3E, 3Z and fulgimides 4E, 4Z.
Scheme 3: Synthesis of fulgide 7E and fulgimide 8E.
Figure 1: Molecular structure of 3Z. Thermal ellipsoids are drawn on the 30% probability level. Selected bond...
Figure 2: Molecular structure of 3E. Thermal ellipsoids are drawn on the 30% probability level. Selected bond...
Scheme 4: Photochemical rearrangements of fulgide 3E followed by1,5-H shift.
Figure 3: Electronic absorption spectra of fulgide 3E in acetonitrile solution before (1) and after irradiati...
Figure 4: Electronic absorption spectra of fulgide 3Z in acetonitrile solution before (1) and after irradiati...
Figure 5: Molecular structure of photoproduct cis-9C’. Thermal ellipsoids are drawn on the 30% probability le...
Scheme 5: Photochemical rearrangements of fulgide 7E followed by1,5-H shift.
Figure 6: Electronic absorption spectra of fulgide 7E in acetonitrile solution before (1) and after irradiati...
Scheme 6: Photochemical rearrangements of fulgimides 4E and 8E followed by1,5-H shift.
Figure 7: Electronic absorption spectra of fulgimide 8E in acetonitrile solution before (1) and after irradia...
When metal-catalyzed C–H functionalization meets visible-light photocatalysis
- Lucas Guillemard and
- Joanna Wencel-Delord
Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147
- et al., allowing the synthesis of N-heterocycles such as indoles and pyrroles. The targeted heterocyclic products were obtained by cyclization of acetanilides with alkyne derivatives via a direct ortho-metalation pathway (Figure 17) [79]. Acetyl substituents acted as DG in this transformation
- heteroarene coupling partners. Indeed, furans, thiophenes, and pyrroles underwent selectively the non-directed C–H functionalization, delivering a diversity of heteroaryl–aryl coupling products. Remarkably, the continuous-flow technique rendered this transformation perfectly suited for large-scale and rapid
Graphical Abstract
Figure 1: Concept of dual synergistic catalysis.
Figure 2: Classification of catalytic systems involving two catalysts.
Figure 3: General mechanism for the dual nickel/photoredox catalytic system.
Figure 4: General mechanisms for C–H activation catalysis involving different reoxidation strategies.
Figure 5: Indole synthesis via dual C–H activation/photoredox catalysis.
Figure 6: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 7: Oxidative Heck reaction on arenes via the dual catalysis.
Figure 8: Proposed mechanism for the Heck reaction on arenes via dual catalysis.
Figure 9: Oxidative Heck reaction on phenols via the dual catalysis.
Figure 10: Proposed mechanism for the Heck reaction on phenols via dual catalysis.
Figure 11: Carbazole synthesis via dual C–H activation/photoredox catalysis.
Figure 12: Proposed mechanism for the carbazole synthesis via dual catalysis.
Figure 13: Carbonylation of enamides via the dual C–H activation/photoredox catalysis.
Figure 14: Proposed mechanism for carbonylation of enamides via dual catalysis.
Figure 15: Annulation of benzamides via the dual C–H activation/photoredox catalysis.
Figure 16: Proposed mechanism for the annulation of benzamides via dual catalysis.
Figure 17: Synthesis of indoles via the dual C–H activation/photoredox catalysis.
Figure 18: Proposed mechanism for the indole synthesis via dual catalysis.
Figure 19: General concept of dual catalysis merging C–H activation and photoredox catalysis.
Figure 20: The first example of dual catalysis merging C–H activation and photoredox catalysis.
Figure 21: Proposed mechanism for the C–H arylation with diazonium salts via dual catalysis.
Figure 22: Dual catalysis merging C–H activation/photoredox using diaryliodonium salts.
Figure 23: Direct arylation via the dual catalytic system reported by Xu.
Figure 24: Direct arylation via dual catalytic system reported by Balaraman.
Figure 25: Direct arylation via dual catalytic system reported by Guo.
Figure 26: C(sp3)–H bond arylation via the dual Pd/photoredox catalytic system.
Figure 27: Acetanilide derivatives acylation via the dual C–H activation/photoredox catalysis.
Figure 28: Proposed mechanism for the C–H acylation with α-ketoacids via dual catalysis.
Figure 29: Acylation of azobenzenes via the dual catalysis C–H activation/photoredox.
Figure 30: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 31: Proposed mechanism for the C2-acylation of indoles with aldehydes via dual catalysis.
Figure 32: C2-acylation of indoles via the dual C–H activation/photoredox catalysis.
Figure 33: Perfluoroalkylation of arenes via the dual C–H activation/photoredox catalysis.
Figure 34: Proposed mechanism for perfluoroalkylation of arenes via dual catalysis.
Figure 35: Sulfonylation of 1-naphthylamides via the dual C–H activation/photoredox catalysis.
Figure 36: Proposed mechanism for sulfonylation of 1-naphthylamides via dual catalysis.
Figure 37: meta-C–H Alkylation of arenes via visible-light metallaphotocatalysis.
Figure 38: Alternative procedure for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 39: Proposed mechanism for meta-C–H alkylation of arenes via metallaphotocatalysis.
Figure 40: C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 41: Proposed mechanism for C–H borylation of arenes via visible-light metallaphotocatalysis.
Figure 42: Undirected C–H aryl–aryl cross coupling via dual gold/photoredox catalysis.
Figure 43: Proposed mechanism for the undirected C–H aryl–aryl cross-coupling via dual catalysis.
Figure 44: Undirected C–H arylation of (hetero)arenes via dual manganese/photoredox catalysis.
Figure 45: Proposed mechanism for the undirected arylation of (hetero)arenes via dual catalysis.
Figure 46: Photoinduced C–H arylation of azoles via copper catalysis.
Figure 47: Photo-induced C–H chalcogenation of azoles via copper catalysis.
Figure 48: Decarboxylative C–H adamantylation of azoles via dual cobalt/photoredox catalysis.
Figure 49: Proposed mechanism for the C–H adamantylation of azoles via dual catalysis.
Figure 50: General mechanisms for the “classical” (left) and Cu-free variant (right) Sonogoshira reaction.
Figure 51: First example of a dual palladium/photoredox catalysis for Sonogashira-type couplings.
Figure 52: Arylation of terminal alkynes with diazonium salts via dual gold/photoredox catalysis.
Figure 53: Proposed mechanism for the arylation of terminal alkynes via dual catalysis.
Figure 54: C–H Alkylation of alcohols promoted by H-atom transfer (HAT).
Figure 55: Proposed mechanism for the C–H alkylation of alcohols promoted by HAT.
Figure 56: C(sp3)–H arylation of latent nucleophiles promoted by H-atom transfer.
Figure 57: Proposed mechanism for the C(sp3)–H arylation of latent nucleophiles promoted by HAT.
Figure 58: Direct α-arylation of alcohols promoted by H-atom transfer.
Figure 59: Proposed mechanism for the direct α-arylation of alcohols promoted by HAT.
Figure 60: C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 61: Proposed mechanism for the C–H arylation of amines via dual Ni/photoredox catalysis.
Figure 62: C–H functionalization of nucleophiles via excited ketone/nickel dual catalysis.
Figure 63: Proposed mechanism for the C–H functionalization enabled by excited ketones.
Figure 64: Selective sp3–sp3 cross-coupling promoted by H-atom transfer.
Figure 65: Proposed mechanism for the selective sp3–sp3 cross-coupling promoted by HAT.
Figure 66: Direct C(sp3)–H acylation of amines via dual Ni/photoredox catalysis.
Figure 67: Proposed mechanism for the C–H acylation of amines via dual Ni/photoredox catalysis.
Figure 68: C–H hydroalkylation of internal alkynes via dual Ni/photoredox catalysis.
Figure 69: Proposed mechanism for the C–H hydroalkylation of internal alkynes.
Figure 70: Alternative procedure for the C–H hydroalkylation of ynones, ynoates, and ynamides.
Figure 71: Allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 72: Proposed mechanism for the allylic C(sp3)–H activation via dual Ni/photoredox catalysis.
Figure 73: Asymmetric allylation of aldehydes via dual Cr/photoredox catalysis.
Figure 74: Proposed mechanism for the asymmetric allylation of aldehydes via dual catalysis.
Figure 75: Aldehyde C–H functionalization promoted by H-atom transfer.
Figure 76: Proposed mechanism for the C–H functionalization of aldehydes promoted by HAT.
Figure 77: Direct C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 78: Proposed mechanism for the C–H arylation of strong aliphatic bonds promoted by HAT.
Figure 79: Direct C–H trifluoromethylation of strong aliphatic bonds promoted by HAT.
Figure 80: Proposed mechanism for the C–H trifluoromethylation of strong aliphatic bonds.
Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts
- Soundararajan Karthikeyan,
- Radha Krishnan Shobana,
- Kamarajapurathu Raju Subimol,
- J. Helen Ratna Monica and
- Ayyanoth Karthik Krishna Kumar
Beilstein J. Org. Chem. 2020, 16, 1579–1587, doi:10.3762/bjoc.16.130
- , heterocycles such as, pyrroles (e.g., IV) [24], keto pyrroles (e.g., V) [25], pyridines (e.g., VI) [26], pyrrolotriazoles (e.g., VII) [27], and triazolobenzoxazonines (e.g., VIII) [28] result from MBH acetates (Scheme 1). From these synthetic elaborations, three successive steps are universally utilized: (i
- reactions. We further extended the scope of this transformation to five-membered heterocyclic MBH adducts. To our delight, except pyrroles, the proposed methodology was amenable to MBH adducts of furan and thiophene (3n–q, 70–80%). The mechanistic pathway for the triazolation proceeded via a nucleophilic
Graphical Abstract
Scheme 1: Literature-reported cycloaddition reactions of MBH acetates involving azides and alkynes [24-28].
Scheme 2: Synthetic methodologies for triazolations of MBH adducts. a) Literature-reported indirect triazolat...
Scheme 3: Scope of the one-pot cascade reaction of the unprotected Morita–Baylis–Hillman adducts 3a–q.
Figure 1: Proposed mechanism for the synthesis of 1,4-disubstituted triazoles.
Scheme 4: Comparative analysis of the sequential one-pot reaction.
Figure 2: Proposed mechanism for the synthesis of 3-(bromomethyl)coumarins.
Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole
- Carlos H. Escalante,
- Eder I. Martínez-Mora,
- Carlos Espinoza-Hicks,
- Alejandro A. Camacho-Dávila,
- Fernando R. Ramos-Morales,
- Francisco Delgado and
- Joaquín Tamariz
Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113
- representative example of the less common approach for the construction of the indole skeleton on substituted pyrroles by generating the benzene ring via an annulation process [36][37][38][39]. Due to our interest in transforming simple five-membered heterocycles into natural products [40][41] and complex aza
- provide compounds 12. To account for the strong endo preference of adducts 9, a computational study was performed to analyze the stationary points on the potential surfaces of the Diels–Alder reactions. Results and Discussion Synthesis Pyrroles 8a–j were prepared through a straightforward and efficient
- phosphonates 15a–c to afford derivatives 8a–f in high yields (Table 1, entries 1–6). For the synthesis of pyrroles 8g,h (R1 = Ac), pyrroles 13c and 13e were subjected to condensation reactions at a higher temperature, with acetone as the nucleophile (instead the phosphonate 15) in the presence of KOH as the
Graphical Abstract
Figure 1: Fused aza-hetero polycyclic frames and natural pyrrolizine- and isoindole-containing alkaloids.
Scheme 1: Synthetic approaches for the preparation of pyrrolo-fused aza-hetero polycyclic frames.
Scheme 2: Preparation of 1,2-substituted pyrroles 8a–f and 8i,j.
Scheme 3: Diels–Alder cycloadditions of pyrroles 8a–j and 16a–b with maleimides 7b–c.
Figure 2: Structures of 9m (a) and 10m (b) as determined by single-crystal X-ray diffraction crystallography ...
Scheme 4: Pd(0)-catalyzed intramolecular Heck cross-coupling reaction of 2-vinylpyrroles 8c,d and 8g.
Scheme 5: Synthesis of 2-vinylpyrroles 8k,l and their Pd(0)-catalyzed intramolecular Heck cross-coupling to p...
Scheme 6: Diastereoselective Diels–Alder reaction of pyrrolo[2,1-a]isoindole 18a with 7c.
Scheme 7: Synthetic approach to the fused aza-heterocyclic pentacycle 12.
Figure 3: M06-2X/6-31+G(d,p) Optimized geometry for each of the SCs (a and d), TSs (b and e) and ADs (c and f...
Figure 4: M06-2X/6-31+G(d,p) Optimized geometry for each of the TSs of the Diels–Alder reactions of dienes 8b...
Figure 5: M06-2X/6-31+G(d,p) Optimized geometry of the endo SCs (a) and TSs (b) for the Diels–Alder reaction ...
Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis
- Stephanie G. E. Amos,
- Marion Garreau,
- Luca Buzzetti and
- Jerome Waser
Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103
- release approach, the Xiao group reported a synthesis of the pyrroles 35.3 in 2014 [153]. They can be accessed via a photocatalytic formal [3 + 2] cycloaddition of the 2H-azirines 35.1 and the alkynes 35.2 (Scheme 35). The use of Mes-Acr-Me+ (OD2) was successful due to its high reduction potential in the
Graphical Abstract
Figure 1: Selected examples of organic dyes. Mes-Acr+: 9-mesityl-10-methylacridinium, DCA: 9,10-dicyanoanthra...
Scheme 1: Activation modes in photocatalysis.
Scheme 2: Main strategies for the formation of C(sp3) radicals used in organophotocatalysis.
Scheme 3: Illustrative example for the photocatalytic oxidative generation of radicals from carboxylic acids:...
Scheme 4: Illustrative example for the photocatalytic reductive generation of C(sp3) radicals from redoxactiv...
Figure 2: Common substrates for the photocatalytic oxidative generation of C(sp3) radicals.
Scheme 5: Illustrative example for the photocatalytic oxidative generation of radicals from dihydropyridines ...
Scheme 6: Illustrative example for the photocatalytic oxidative generation of C(sp3) radicals from trifluorob...
Scheme 7: Illustrative example for the photocatalytic reductive generation of C(sp3) radicals from benzylic h...
Scheme 8: Illustrative example for the photocatalytic generation of C(sp3) radicals via direct HAT: the cross...
Scheme 9: Illustrative example for the photocatalytic generation of C(sp3) radicals via indirect HAT: the deu...
Scheme 10: Selected precursors for the generation of aryl radicals using organophotocatalysis.
Scheme 11: Illustrative example for the photocatalytic reductive generation of aryl radicals from aryl diazoni...
Scheme 12: Illustrative examples for the photocatalytic reductive generation of aryl radicals from haloarenes:...
Scheme 13: Illustrative example for the photocatalytic reductive generation of aryl radicals from aryl halides...
Scheme 14: Illustrative example for the photocatalytic reductive generation of aryl radicals from arylsulfonyl...
Scheme 15: Illustrative example for the reductive photocatalytic generation of aryl radicals from triaryl sulf...
Scheme 16: Main strategies towards acyl radicals used in organophotocatalysis.
Scheme 17: Illustrative example for the decarboxylative photocatalytic generation of acyl radicals from α-keto...
Scheme 18: Illustrative example for the oxidative photocatalytic generation of acyl radicals from acyl silanes...
Scheme 19: Illustrative example for the oxidative photocatalytic generation of carbamoyl radicals from 4-carba...
Scheme 20: Illustrative example of the photocatalytic HAT approach for the generation of acyl radicals from al...
Scheme 21: General reactivity of a) radical cations; b) radical anions; c) the main strategies towards aryl an...
Scheme 22: Illustrative example for the oxidative photocatalytic generation of alkene radical cations from alk...
Scheme 23: Illustrative example for the reductive photocatalytic generation of an alkene radical anion from al...
Figure 3: Structure of C–X radical anions and their neutral derivatives.
Scheme 24: Illustrative example for the photocatalytic reduction of imines and the generation of an α-amino C(...
Scheme 25: Illustrative example for the oxidative photocatalytic generation of aryl radical cations from arene...
Scheme 26: NCR classifications and generation.
Scheme 27: Illustrative example for the photocatalytic reductive generation of iminyl radicals from O-aryl oxi...
Scheme 28: Illustrative example for the photocatalytic oxidative generation of iminyl radicals from α-N-oxy ac...
Scheme 29: Illustrative example for the photocatalytic oxidative generation of iminyl radicals via an N–H bond...
Scheme 30: Illustrative example for the photocatalytic oxidative generation of amidyl radicals from Weinreb am...
Scheme 31: Illustrative example for the photocatalytic reductive generation of amidyl radicals from hydroxylam...
Scheme 32: Illustrative example for the photocatalytic reductive generation of amidyl radicals from N-aminopyr...
Scheme 33: Illustrative example for the photocatalytic oxidative generation of amidyl radicals from α-amido-ox...
Scheme 34: Illustrative example for the photocatalytic oxidative generation of aminium radicals: the N-aryltet...
Scheme 35: Illustrative example for the photocatalytic oxidative generation of nitrogen-centered radical catio...
Scheme 36: Illustrative example for the photocatalytic oxidative generation of nitrogen-centered radical catio...
Scheme 37: Illustrative example for the photocatalytic oxidative generation of hydrazonyl radical from hydrazo...
Scheme 38: Generation of O-radicals.
Scheme 39: Illustrative examples for the photocatalytic generation of O-radicals from N-alkoxypyridinium salts...
Scheme 40: Illustrative examples for the photocatalytic generation of O-radicals from alkyl hydroperoxides: th...
Scheme 41: Illustrative example for the oxidative photocatalytic generation of thiyl radicals from thiols: the...
Scheme 42: Main strategies and reagents for the generation of sulfonyl radicals used in organophotocatalysis.
Scheme 43: Illustrative example for the reductive photocatalytic generation of sulfonyl radicals from arylsulf...
Scheme 44: Illustrative example of a Cl atom abstraction strategy for the photocatalytic generation of sulfamo...
Scheme 45: Illustrative example for the oxidative photocatalytic generation of sulfonyl radicals from sulfinic...
Scheme 46: Illustrative example for the photocatalytic generation of electronically excited triplet states: th...
Scheme 47: Illustrative example for the photocatalytic generation of electronically excited triplet states: th...
Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties
- Liliia Moshniaha,
- Marika Żyła-Karwowska,
- Joanna Cybińska,
- Piotr J. Chmielewski,
- Ludovic Favereau and
- Marcin Stępień
Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81
- measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials. Keywords: donor–acceptor systems; double C–H bond activation; helicenes; pyrroles; Introduction Nanographenes and other polycyclic aromatics as well as their heterocyclic analogues are typically
Graphical Abstract
Scheme 1: The previously reported family of the boomerang bipyrroles obtained by Pd-induced double C–H bond a...
Scheme 2: Synthesis and structures of α-free and α-oxygenated bipyrrole boomerangs. Reagents and conditions: ...
Figure 1: DFT-Optimized structures (B3LYP/6-31G(d,p)) of cNDA2O and cNMI3H.
Figure 2: Absorption and emission spectra of cNMI2H (top) and cNMI3H (bottom) measured in toluene, dichlorome...
Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties
- Takahide Shimada,
- Shigeki Mori,
- Masatoshi Ishida and
- Hiroyuki Furuta
Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53
- BODIPY core has not yet been achieved. Inspired by the works of Waser and co-workers showing the gold(I)-catalyzed C–H electrophilic alkynylation of various heterocycles (e.g., pyrroles, indoles, etc.) with ethynylbenziodoxolone (EBX) as an activated ethynyl synthon [38][39][40][41][42], we investigated
Graphical Abstract
Figure 1: (a) Chemical structures of BODIPY (1) and dipyrromethane (2). (b) C–C bond forming alkynylations of...
Scheme 1: Synthesis of α-ethynyl-substituted BODIPY derivatives 3a and 4a.
Scheme 2: Synthesis of β-ethynyl-substituted BODIPY derivatives 5a and 5b and β,β'-diethynyl-substituted comp...
Figure 2: Top and front views of the crystal structures of (a) 4a and (b) 6b with 50% thermal ellipsoid proba...
Figure 3: Partial 1H NMR spectra of (a) 1a, (b) 3a, (c) 4a, (d) 5a, and (e) 6a recorded in CDCl3 at 298 K. As...
Figure 4: UV–vis absorption spectra of the BODIPY derivatives, (a) 1a (green), 3a (blue), 4a (red), and (b) 1a...
Figure 5: Fluorescence spectra of BODIPY derivatives. (a) 1a (green), 3a (blue), 4a (red) and (b) 1a (green), ...
Recent advances in photocatalyzed reactions using well-defined copper(I) complexes
- Mingbing Zhong,
- Xavier Pannecoucke,
- Philippe Jubault and
- Thomas Poisson
Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42
- excellent yields. Finally, a Meerwein arylation reaction was developed through the copper photocatalyzed formation of an aryl radical according to a reductive process. A large panel of aryl iodides was added to various pyrroles and electron-rich aromatic derivatives. The arylated products were obtained in
Graphical Abstract
Scheme 1: [Cu(I)(dap)2]Cl-catalyzed ATRA reaction under green light irradiation.
Scheme 2: Photocatalytic allylation of α-haloketones.
Scheme 3: [Cu(I)(dap)2]Cl-photocatalyzed chlorosulfonylation and chlorotrifluoromethylation of alkenes.
Scheme 4: Photocatalytic perfluoroalkylchlorination of electron-deficient alkenes using the Sauvage catalyst.
Scheme 5: Photocatalytic synthesis of fluorinated sultones.
Scheme 6: Photocatalyzed haloperfluoroalkylation of alkenes and alkynes.
Scheme 7: Chlorosulfonylation of alkenes catalyzed by [Cu(I)(dap)2]Cl. aNo Na2CO3 was added. b1 equiv of Na2CO...
Scheme 8: Copper-photocatalyzed reductive allylation of diaryliodonium salts.
Scheme 9: Copper-photocatalyzed azidomethoxylation of olefins.
Scheme 10: Benzylic azidation initiated by [Cu(I)(dap)2]Cl.
Scheme 11: Trifluoromethyl methoxylation of styryl derivatives using [Cu(I)(dap)2]PF6. All redox potentials ar...
Scheme 12: Trifluoromethylation of silyl enol ethers.
Scheme 13: Synthesis of annulated heterocycles upon oxidation with the Sauvage catalyst.
Scheme 14: Oxoazidation of styrene derivatives using [Cu(dap)2]Cl as a precatalyst.
Scheme 15: [Cu(I)(dpp)(binc)]PF6-catalyzed ATRA reaction.
Scheme 16: Allylation reaction of α-bromomalonate catalyzed by [Cu(I)(dpp)(binc)]PF6 following an ATRA mechani...
Scheme 17: Bromo/tribromomethylation reaction using [Cu(I)(dmp)(BINAP)]PF6.
Scheme 18: Chlorotrifluoromethylation of alkenes catalyzed by [Cu(I)(N^N)(xantphos)]PF6.
Scheme 19: Chlorosulfonylation of styrene and alkyne derivatives by ATRA reactions.
Scheme 20: Reduction of aryl and alkyl halides with the complex [Cu(I)(bcp)(DPEPhos)]PF6. aIrradiation was car...
Scheme 21: Meerwein arylation of electron-rich aromatic derivatives and 5-exo-trig cyclization catalyzed by th...
Scheme 22: [Cu(I)(bcp)(DPEPhos)]PF6-photocatalyzed synthesis of alkaloids. aYield over two steps (cyclization ...
Scheme 23: Copper-photocatalyzed decarboxylative amination of NHP esters.
Scheme 24: Photocatalytic decarboxylative alkynylation using [Cu(I)(dq)(binap)]BF4.
Scheme 25: Copper-photocatalyzed alkylation of glycine esters.
Scheme 26: Copper-photocatalyzed borylation of organic halides. aUnder continuous flow conditions.
Scheme 27: Copper-photocatalyzed α-functionalization of alcohols with glycine ester derivatives.
Scheme 28: δ-Functionalization of alcohols using [Cu(I)(dmp)(xantphos)]BF4.
Scheme 29: Photocatalytic synthesis of [5]helicene and phenanthrene.
Scheme 30: Oxidative carbazole synthesis using in situ-formed [Cu(I)(dmp)(xantphos)]BF4.
Scheme 31: Copper-photocatalyzed functionalization of N-aryl tetrahydroisoquinolines.
Scheme 32: Bicyclic lactone synthesis using a copper-photocatalyzed PCET reaction.
Scheme 33: Photocatalytic Pinacol coupling reaction catalyzed by [Cu(I)(pypzs)(BINAP)]BF4. The ligands of the ...
Scheme 34: Azide photosensitization using a Cu-based photocatalyst.
AgNTf2-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives
- Ziping Cao,
- Jiekun Zhu,
- Li Liu,
- Yuanling Pang,
- Laijin Tian,
- Xuejun Sun and
- Xin Meng
Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255
- carbene and subsequent cyclization to pyrroles (Scheme 2b). Herein we want to provide some detailed results on the reaction (Scheme 2b), leading to the synthesis of a variety of functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives in high yields. The reaction features the use of an inexpensive
- alkylated ynamides such as 4j gave a complex mixture under current conditions, and no desired product (10ja) was isolated. Subsequently, the N-substituents of ynamides were investigated. The results showed that other alkyl (iPr-, n-Bu- and Bn-) and phenyl are compatible for this reaction, and the pyrroles
Graphical Abstract
Scheme 1: Two modes of reactions of alkynes by silver catalysis.
Scheme 2: Reactions of ynamides or ynol ethers with isoxazoles by transition metal catalysis.
Figure 1: Selected bioactive molecules containing the 5-amino-1H-pyrrole-3-carboxamide motif.
Scheme 3: Reactions of ynamide 4a with different isoxazoles 5, 7 and 8a.
Figure 2: Scope with regard to ynamide 4. All reactions were carried out with ynamide 4 (0.2 mmol), isoxazole ...
Figure 3: Scope with regard to the 5-aminoisoxazole 8 (see Figure 2). aReaction conditions: 2.0 equiv of 8e, 100 °C.
Figure 4: Molecular structure in the solid state of compound 10ad.
Scheme 4: A gram-scale experiment.
Scheme 5: Mechanistic hypotheses for Ag-catalyzed reaction of ynamide 4a with aminoisoxazole 8a.
Scheme 6: Possible reaction routes of intermediate C.
Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups
- Xiaowei Li,
- Xiaolin Shi,
- Xiangqian Li and
- Dayong Shi
Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218
Graphical Abstract
Scheme 1: The main three strategies of fluorination: nucleophilic, electrophilic and radical fluorination.
Scheme 2: Doyle’s Pd-catalyzed fluorination of allylic chlorides.
Scheme 3: Allylic fluorination of 2- and 3-substituted propenyl esters.
Scheme 4: Regioselective allylic fluorination of cinnamyl phosphorothioate esters.
Scheme 5: Palladium-catalyzed aliphatic C–H fluorination reported by Doyle.
Scheme 6: Pd-catalyzed enantioselective fluorination of α-ketoesters followed by stereoselective reduction to...
Scheme 7: Pd-catalyzed C(sp3)–H fluorination of oxindoles.
Scheme 8: C–H fluorination of 8-methylquinoline derivatives with F− reagents.
Scheme 9: Fluorination of α-cyano acetates reported by van Leeuwen.
Scheme 10: The catalytic enantioselective electrophilic C–H fluorination of α-chloro-β-keto phosphonates.
Scheme 11: Fluorination of unactivated C(sp3)–H bonds directed by the bidentate PIP auxiliary.
Scheme 12: Fluorination of C(sp3)–H bonds at the β-position of carboxylic acids.
Scheme 13: Enantioselective benzylic C–H fluorination with a chiral transient directing group.
Scheme 14: Microwave-heated Pd-catalyzed fluorination of aryl alcohols.
Scheme 15: Fluorination of aryl potassium trifluoroborates.
Scheme 16: C(sp2)–F bond formation using precatalyst [L·Pd]2(cod).
Scheme 17: Pd-catalyzed fluorination of (hetero)aryl triflates and bromides.
Scheme 18: The Pd-catalyzed C–H fluorination of arenes with Selectfluor/NFSI.
Scheme 19: Pd(II)-catalyzed ortho-monofluorination protocol for benzoic acids.
Scheme 20: Pd-catalyzed C(sp2)–H bond fluorination of 2-arylbenzothiazoles.
Scheme 21: Nitrate-promoted fluorination of aromatic and olefinic C(sp2)–H bonds and proposed mechanism.
Scheme 22: Fluorination of oxalyl amide-protected benzylamine derivatives.
Scheme 23: C–H fluorination of benzaldehydes with orthanilic acids as transient directing group.
Scheme 24: Pd(II)-catalyzed aryl C–H fluorination with various directing groups.
Scheme 25: Cu-catalyzed aliphatic, allylic, and benzylic fluorination.
Scheme 26: Cu-catalyzed SN2 fluorination of primary and secondary alkyl bromides.
Scheme 27: Copper-catalyzed fluorination of alkyl triflates.
Scheme 28: Cu-catalyzed fluorination of allylic bromides and chlorides.
Scheme 29: Synthetic strategy for the fluorination of active methylene compounds.
Scheme 30: Fluorination of β-ketoesters using a tartrate-derived bidentate bisoxazoline-Cu(II) complex.
Scheme 31: Highly enantioselective fluorination of β-ketoesters and N-Boc-oxindoles.
Scheme 32: Amide group-assisted site-selective fluorination of α-bromocarbonyl compounds.
Scheme 33: Cu-mediated aryl fluorination reported by Sanford [77].
Scheme 34: Mono- or difluorination reactions of benzoic acid derivatives.
Scheme 35: Cu-catalyzed fluorination of diaryliodonium salts with KF.
Scheme 36: Copper(I)-catalyzed cross-coupling of 2-pyridylaryl bromides.
Scheme 37: AgNO3-catalyzed decarboxylative fluorination of aliphatic carboxylic acids.
Scheme 38: The Mn-catalyzed aliphatic and benzylic C–H fluorination.
Scheme 39: Iron(II)-promoted C–H fluorination of benzylic substrates.
Scheme 40: Ag-catalyzed fluorodecarboxylation of carboxylic acids.
Scheme 41: Vanadium-catalyzed C(sp3)–H fluorination.
Scheme 42: AgNO3-catalyzed radical deboronofluorination of alkylboronates and boronic acids.
Scheme 43: Selective heterobenzylic C–H fluorination with Selectfluor reported by Van Humbeck.
Scheme 44: Fe(II)-catalyzed site-selective fluorination guided by an alkoxyl radical.
Scheme 45: Fluorination of allylic trichloroacetimidates reported by Nguyen et al.
Scheme 46: Iridium-catalyzed fluorination of allylic carbonates with TBAF(t-BuOH)4.
Scheme 47: Iridium-catalyzed asymmetric fluorination of allylic trichloroacetimidates.
Scheme 48: Cobalt-catalyzed α-fluorination of β-ketoesters.
Scheme 49: Nickel-catalyzed α-fluorination of various α-chloro-β-ketoesters.
Scheme 50: Ni(II)-catalyzed enantioselective fluorination of oxindoles and β-ketoesters.
Scheme 51: Scandium(III)-catalyzed asymmetric C–H fluorination of unprotected 3-substituted oxindoles.
Scheme 52: Iron-catalyzed directed C–H fluorination.
Scheme 53: Electrophilic silver-catalyzed Ar–F bond-forming reaction from arylstannanes.
Figure 1: Nucleophilic, electrophilic and radical CF3 sources.
Scheme 54: Cu(I)-catalyzed allylic trifluoromethylation of unactivated terminal olefins.
Scheme 55: Direct copper-catalyzed trifluoromethylation of allylsilanes.
Scheme 56: Cupper-catalyzed enantioselective trifluoromethylation of five and six-membered ring β-ketoesters.
Scheme 57: Cu-catalyzed highly stereoselective trifluoromethylation of secondary propargyl sulfonates.
Scheme 58: Remote C(sp3)–H trifluoromethylation of carboxamides and sulfonamides.
Scheme 59: Trifluoromethylation of allylsilanes with photoredox catalysis.
Scheme 60: Ag-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids in aqueous CH3CN.
Scheme 61: Decarboxylative trifluoromethylation of aliphatic carboxylic acids via combined photoredox and copp...
Scheme 62: Palladium-catalyzed Ar–CF3 bond-forming reaction.
Scheme 63: Palladium-catalyzed trifluoromethylation of arenes with diverse heterocyclic directing groups.
Scheme 64: Pd-catalyzed trifluoromethylation of indoles as reported by Liu.
Scheme 65: Pd-catalyzed trifluoromethylation of vinyl triflates and vinyl nonaflates.
Scheme 66: Pd(II)-catalyzed ortho-trifluoromethylation of aromatic C–H bonds.
Scheme 67: Visible-light-induced Pd(OAc)2-catalyzed ortho-trifluoromethylation of acetanilides with CF3SO2Na.
Scheme 68: CuI-catalyzed trifluoromethylation of aryl- and alkenylboronic acids.
Scheme 69: Cu-catalyzed trifluoromethylation of aryl- and vinylboronic acids.
Scheme 70: Copper-catalyzed trifluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 71: Formation of C(sp2)–CF3 bond catalyzed by copper(I) complex.
Scheme 72: Loh’s Cu(I)-catalyzed trifluoromethylation of enamides and electron-deficient alkenes.
Scheme 73: Copper and iron-catalyzed decarboxylative tri- and difluoromethylation.
Scheme 74: Cu-catalyzed trifluoromethylation of hydrazones developed by Bouyssi.
Scheme 75: Cu(I)-catalyzed trifluoromethylation of terminal alkenes.
Scheme 76: Cu/Ag-catalyzed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 77: Copper-catalyzed direct alkenyl C–H trifluoromethylation.
Scheme 78: Copper(I/II)-catalyzed direct trifluoromethylation of styrene derivatives.
Scheme 79: Regioselective trifluoromethylation of pivalamido arenes and heteroarenes.
Scheme 80: Synthesis of trifluoromethylquinones in the presence of copper(I).
Scheme 81: Oxidative trifluoromethylation of imidazoheterocycles in ionic liquid/water.
Scheme 82: A mild and fast continuous-flow trifluoromethylation of coumarins using a CuI/CF3SO2Na/TBHP system.
Scheme 83: Copper-catalyzed oxidative trifluoromethylation of various 8-aminoquinolines.
Scheme 84: PA-directed copper-catalyzed trifluoromethylation of anilines.
Scheme 85: Trifluoromethylation of potassium vinyltrifluoroborates catalyzed by Fe(II).
Scheme 86: Alkenyl trifluoromethylation catalyzed by Ru(phen)3Cl2 as photocatalyst.
Scheme 87: Ru-catalyzed trifluoromethylation of alkenes by Akita’s group.
Scheme 88: Ir-catalyzed Cvinyl–CF3 bond formation of α,β-unsaturated carboxylic acids.
Scheme 89: Ag(I)-catalyzed denitrative trifluoromethylation of β-nitrostyrenes.
Scheme 90: Photocatalyzed direct trifluoromethylation of aryl and heteroaryl C–H bonds.
Scheme 91: Rhenium (MTO)-catalyzed direct trifluoromethylation of aromatic substrates.
Scheme 92: Trifluoromethylation of unprotected anilines under [Ir(ppy)3] catalyst.
Scheme 93: Oxidative trifluoromethylation of imidazopyridines and imidazoheterocycles.
Scheme 94: Ruthenium-catalyzed trifluoromethylation of (hetero)arenes with trifluoroacetic anhydride.
Scheme 95: Phosphovanadomolybdic acid-catalyzed direct C–H trifluoromethylation.
Scheme 96: Picolinamide-assisted ortho-trifluoromethylation of arylamines.
Scheme 97: A nickel-catalyzed C–H trifluoromethylation of free anilines.
Scheme 98: Cu-mediated trifluoromethylation of terminal alkynes reported by Qing.
Scheme 99: Huang’s C(sp)–H trifluoromethylation using Togni’s reagent.
Scheme 100: Cu-catalyzed methods for trifluoromethylation with Umemoto’s reagent.
Scheme 101: The synthesis of alkynyl-CF3 compounds in the presence of fac-[Ir(ppy)3] under visible-light irradi...
Scheme 102: Pd-catalyzed Heck reaction reported by Reutrakul.
Scheme 103: Difluoromethylation of enamides and ene-carbamates.
Scheme 104: Difluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 105: Copper-catalyzed direct C(sp2)–H difluoroacetylation reported by Pannecoucke and co-workers.
Scheme 106: Difluoroalkylation of aldehyde-derived hydrazones with functionalized difluoromethyl bromides.
Scheme 107: Photoredox-catalyzed C–H difluoroalkylation of aldehyde-derived hydrazones.
Scheme 108: Synergistic ruthenium(II)-catalyzed C–H difluoromethylation reported by Ackermann.
Scheme 109: Visible-light photocatalytic decarboxylation of α,β-unsaturated carboxylic acids.
Scheme 110: Synthesis of difluorinated ketones via S-alkyl dithiocarbamates obtained from acyl chlorides and po...
Scheme 111: Synthesis of aryl and heteroaryl difluoromethylated phosphonates.
Scheme 112: Difluoroalkylation of secondary propargyl sulfonates using Cu as the catalyst.
Scheme 113: Ru(II)-mediated para-selective difluoromethylation of anilides and their derivatives.
Scheme 114: Bulky diamine ligand promoted cross-coupling of difluoroalkyl bromides.
Scheme 115: Copper-catalyzed C3–H difluoroacetylation of quinoxalinones.
Scheme 116: Copper(I) chloride-catalyzed trifluoromethylthiolation of enamines, indoles and β-ketoesters.
Scheme 117: Copper-boxmi-catalyzed asymmetric trifluoromethylthiolation of β-ketoesters.
Scheme 118: Direct Cu-catalyzed trifluoromethylthiolation of boronic acids and alkynes.
Scheme 119: Cu-catalyzed synthesis of α-trifluoromethylthio-substituted ketones.
Scheme 120: Trifluoromethylthiolation reactions promoted by diazotriflone and copper.
Scheme 121: Halide activation of N-(trifluoromethylthio)phthalimide.
Scheme 122: The visible light-promoted trifluoromethylthiolation reported by Glorius.
Scheme 123: Synthesis of α-trifluoromethylthioesters via Goossen’s approach.
Scheme 124: Photoinduced trifluoromethylthiolation of diazonium salts.
Scheme 125: Ag-mediated trifluoromethoxylation of aryl stannanes and arylboronic acids.
Scheme 126: Catalytic (hetero)aryl C–H trifluoromethoxylation under visible light.
Scheme 127: Photoinduced C–H-bond trifluromethoxylation of (hetero)arenes.
Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids
- Jürgen Krauß,
- Monika Klimt,
- Markus Luber,
- Peter Mayer and
- Franz Bracher
Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206
- investigated here, even direct protonation at C-3 of the pyrrole by strong acid is most likely, due to the significant basicity of pyrroles. Delocalization of the positive charge (A ↔ A’) as shown in Scheme 2 will support the initial ring protonation step. The X-ray analysis of compound 7 revealed that the
Graphical Abstract
Figure 1: Atorvastatin calcium trihydrate (1) and previously published decomposition products arising from tr...
Scheme 1: Formation of novel artefacts 6 and 7 under extremely strong acidic conditions.
Figure 2: Top: Molecular structure of artefact 6. Shown here is the molecular structure of one of three indep...
Figure 3: Separation of atorvastatin (1; retention time: 5.8 min) from the four decomposition products 2 (ret...
Scheme 2: Proposed mechanism for the formation of desamidated product 7.
Scheme 3: Proposed mechanism for the formation of bridged product 6 under cyclization, isopropyl migration an...
Regioselective Pd-catalyzed direct C1- and C2-arylations of lilolidine for the access to 5,6-dihydropyrrolo[3,2,1-ij]quinoline derivatives
- Hai-Yun Huang,
- Haoran Li,
- Thierry Roisnel,
- Jean-François Soulé and
- Henri Doucet
Beilstein J. Org. Chem. 2019, 15, 2069–2075, doi:10.3762/bjoc.15.204
- functionalization of heteroarenes such as thiophenes, furans, pyrroles and indoles [14][15], this methodology has been widely applied for the preparation of new aryl-substituted heteroarenes [16][17][18][19][20][21]. Several results dealing with the C–H bond functionalization of indoles have been reported allowing
Graphical Abstract
Figure 1: Structures of lilolidine, tivantinib and tarazepide.
Scheme 1: Access to α- and β-arylated lilolidine derivatives.
Scheme 2: Synthesis of α-arylated lilolidine derivatives.
Scheme 3: Synthesis of α,β-di(hetero)arylated lilolidine derivatives.
Scheme 4: Synthesis of α,β-diarylated lilolidine derivatives via successive direct arylations.
Scheme 5: Synthesis of 5,6-dihydrodibenzo[a,c]pyrido[3,2,1-jk]carbazoles via successive direct arylations.
Annulation of 1H-pyrrole-2,3-diones by thioacetamide: an approach to 5-azaisatins
- Aleksandr I. Kobelev,
- Ekaterina E. Stepanova,
- Maksim V. Dmitriev and
- Andrey N. Maslivets
Beilstein J. Org. Chem. 2019, 15, 364–370, doi:10.3762/bjoc.15.32
- and Discussion Previously, we reported an efficient catalyst-free synthesis of spiro[thiazolo-5,2'-pyrroles] 1 via interaction of pyrrolobenzoxazinetriones (PBTs) 2 with thiobenzamide (Scheme 2) [17][18]. In continuation of this research [17][18], and in order to extend the scope of the reaction, we
- attempted to involve the simplest aliphatic thioamide, thioacetamide, in the interaction with PBTs 2. As a result, we obtained the expected spiro[thiazolo-5,2'-pyrroles] 3, which were found to exist in a form with an exo-methylene group according to the NMR spectra (Scheme 3) [19]. Unfortunately, the
- '-pyrroles] 3. It could be either a molecule of the spiro[thiazolo-5,2'-pyrrole] 3 or a molecule of the PBT 2. To determine the most possible one, we investigated the effect of the ratio of the reagents. When we used excessive amounts of thioacetamide (fivefold excess to PBT 2a), a significant decrease in
Graphical Abstract
Scheme 1: Approaches to the synthesis of the 5-azaisatin core.
Scheme 2: Our previous work on the interaction of PBTs 2 with thioamides.
Scheme 3: Interaction of PBTs 2 with thioacetamide.
Scheme 4: Plausible pathways for the formation of compound 4.
Scheme 5: Experiments on the intermolecular trapping of spiro[thiazolo-5,2'-pyrrole] 3a.
Scheme 6: Exploration of the substrate scope.
Scheme 7: Interaction of PBT 2a with N-phenylthioacetamide.
Mn-mediated sequential three-component domino Knoevenagel/cyclization/Michael addition/oxidative cyclization reaction towards annulated imidazo[1,2-a]pyridines
- Olga A. Storozhenko,
- Alexey A. Festa,
- Delphine R. Bella Ndoutoume,
- Alexander V. Aksenov,
- Alexey V. Varlamov and
- Leonid G. Voskressensky
Beilstein J. Org. Chem. 2018, 14, 3078–3087, doi:10.3762/bjoc.14.287
- oxidative conditions has been developed. The employment of Mn(OAc)3·2H2O or KMnO4 as stoichiometric oxidants allowed the use of a wide range of nucleophiles, such as nitromethane, (aza)indoles, pyrroles, phenols, pyrazole, indazole and diethyl malonate. The formation of the target compounds presumably
Graphical Abstract
Figure 1: Biologically relevant imidazo[1,2-a]pyridines and chromenes.
Scheme 1: Domino formation of imidazopyridines and current work.
Scheme 2: Scope of the reaction between N-(cyanomethyl)pyridinium chloride, o-hydroxybenzaldehydes, and nitro...
Scheme 3: Scope of the reaction of o-hydroxybenzaldehydes with N-(cyanomethyl)pyridinium chloride and indoles...
Scheme 4: Scope of the nucleophiles in the reaction of o-hydroxyarylaldehydes with N-(cyanomethyl)pyridinium ...
Scheme 5: N-(Cyanomethyl)thieno[2,3-c]pyridinium chloride (15) and 6-(cyanomethyl)-1-methyl-1H-pyrrolo[2,3-c]...
Figure 2: General view of the molecule 7b in the crystal state (CCDC 1849215). Anisotropic displacement param...
Scheme 6: The presumed mechanism for the formation of target chromenoimidazopyridines (reaction 1) and additi...
Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions
- Stanislav V. Lozovskiy,
- Alexander Yu. Ivanov,
- Olesya V. Khoroshilova and
- Aleksander V. Vasilyev
Beilstein J. Org. Chem. 2018, 14, 2897–2906, doi:10.3762/bjoc.14.268
- recently shown [8]. These allenes give rise to pyrrolidines [9], pyrroles [10], chromenes [11], benzoazepinones [12], macrolides [13], and some other carbo- and heterocycles [14][15][16]. It should be specially emphasized that many compounds containing SO2 groups are drugs, such as, dapson [17], oxicams
Graphical Abstract
Scheme 1: (Arylsulfinyl)allenes 1 and (arylsulfonyl)allenes 2 used in this study.
Figure 1: X-ray crystal structures of compounds 2h (CCDC 1843276), 3e (CCDC 1843277), 5c (CCDC 1580895), 7b (...
Scheme 2: Plausible reaction mechanisms of transformations of allene 2a in Brønsted acids.
Scheme 3: Selective formation of butadienes 3a–h from allenes 2a–h.
Scheme 4: Reactions of allenes 2 in the system HFIP/TfOH followed by interaction with nucleophiles leading to...
Scheme 5: Formation of thiochromene 1,1-dioxides 5a–c from allenes 2a,c,d.
Scheme 6: Formation of (arylsulfonyl)acetones 6a,b from allenes 2h,j in TfOH (100 °C, 0.5 h) followed by hydr...
Scheme 7: Reactions of (arylsulfinyl)allenes 1a,b under superelectrophilic activation.
An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes
- Hashem Sharghi,
- Pezhman Shiri and
- Mahdi Aberi
Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253
- –270 °C for 20 h, (e) after filtration, washing, and drying, MWCNTs-SO3H composite 97 was achieved (Scheme 17). N-Substituted pyrroles 99 were obtained in good to excellent yields (40–92%) via a simple and green reaction between 2,5-dimethoxytetrahydrofuran (98) and primary amines 15 in water media at
Graphical Abstract
Figure 1: Different types of sulfonated materials as acid catalysts.
Scheme 1: Synthetic route of 3-methyl-1-sulfo-1H-imidazolium metal chloride ILs and their catalytic applicati...
Scheme 2: Synthetic route of 1,3-disulfo-1H-imidazolium transition metal chloride ILs and their catalytic app...
Scheme 3: Synthetic route of 1,3-disulfoimidazolium carboxylate ILs and their catalytic applications in the s...
Scheme 4: Synthetic route of [BiPy](HSO3)2Cl2 and [Dsim]HSO4 ILs and their catalytic applications for the syn...
Scheme 5: The catalytic applications of (C4(DABCO-SO3H)2·4Cl) IL for the synthesis of spiro-isatin derivative...
Scheme 6: The catalytic applications of (C4(DABCO-SO3H)2·4Cl) IL for the synthesis of bis 2-amino-4H-pyran de...
Scheme 7: The synthetic route of N,N-disulfo-1,1,3,3-tetramethylguanidinium carboxylate ILs and their catalyt...
Scheme 8: The catalytic application of 1-methyl-3-sulfo-1H-imidazolium tetrachloroferrate IL in the synthesis...
Scheme 9: The synthetic route of 3-sulfo-1H-imidazolopyrimidinium hydrogen sulfate IL and its catalytic appli...
Scheme 10: The results for the synthesis of bis(indolyl)methanes and di(bis(indolyl)methyl)benzenes in the pre...
Scheme 11: The catalytic applications of 1-(1-sulfoalkyl)-3-methylimidazolium chloride acidic ILs for the hydr...
Scheme 12: The synthetic route of immobilized 1,4-diazabicyclo[2.2.2]octanesulfonic acid chloride on SiO2 and ...
Scheme 13: The catalytic application of a silica-bonded sulfoimidazolium chloride for the synthesis of 12-aryl...
Scheme 14: The synthetic route of the SBA-15-Ph-SO3H and its catalytic applications for the synthesis of 2H-in...
Scheme 15: The synthetic route for heteropolyanion-based ionic liquids immobilized on mesoporous silica SBA-15...
Scheme 16: Some mechanism aspects of SSA catalyst for the protection of amine derivatives.
Scheme 17: The synthetic route for MWCNT-SO3H and its catalytic application for the synthesis of N-substituted...
Scheme 18: The sulfonic acid-functionalized polymers (P-SO3H) covalently grafted on multi-walled carbon nanotu...
Scheme 19: The transesterification reaction in the presence of S-MWCNTs.
Scheme 20: The synthetic route for the new hypercrosslinked supermicroporous polymer via the Friedel–Crafts al...
Scheme 21: The synthetic route for a new microporous copolymer via the Friedel–Crafts alkylation reaction of t...
Scheme 22: The synthetic route for sulfonated polynaphthalene and its catalytic application for the amidoalkyl...
Scheme 23: The synthetic route of the acidic carbon material and its catalytic application in the etherificatio...
Scheme 24: The synthetic route of the acidic carbon materials and their catalytic applications for the esterif...
Scheme 25: The sulfonated MWCNTs.
Scheme 26: The sulfonated nanoscaled diamond powder for the dehydration of D-xylose into furfural.
Scheme 27: The synthetic route and catalytic application of the GR-SO3H.
Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles
- Takashi Go,
- Akane Morimatsu,
- Hiroaki Wasada,
- Genzoh Tanabe,
- Osamu Muraoka,
- Yoshiharu Sawada and
- Mitsuhiro Yoshimatsu
Beilstein J. Org. Chem. 2018, 14, 2722–2729, doi:10.3762/bjoc.14.250
- -diynes with secondary amines resulted in the formation of 3-sulfanylmethyl-4-aminomethylpyrroles (Scheme 1) [32][33]. The sulfanyl group of pyrroles is easily oxidised to produce their corresponding sulfoxides. When we performed the Pummerer reaction and cyclization of pyrrolesulfoxides to obtain their
Graphical Abstract
Scheme 1: Our synthetic plan for pyrrolo[3,2-c]azepines.
Scheme 2: Preparation of precursors for the Pummerer reactions.
Scheme 3: Substrate scope of 1,7-S and 1,7-Se shift reactions.
Scheme 4: Proposed mechanism.
Scheme 5: Crossover experiment.
Scheme 6: Lewis acid-catalysed cyclization of diols.
Scheme 7: Sequential process of sulfanyl-1,6-diyne 1 to 4H-pyrrolo[3,4-g]oxazine 25g.
Learning from B12 enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis
- Keishiro Tahara,
- Ling Pan,
- Toshikazu Ono and
- Yoshio Hisaeda
Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232
- Cobalamins (B12) are naturally occurring cobalt complexes with unique structures that play various important roles in vivo [1][2][3][4][5]. In B12, the cobalt center is coordinated by four equatorial pyrroles of the corrin ring and 2,3-dimethylbenzimidazole as a lower axial ligand (Figure 1a) [6][7][8]. The
Graphical Abstract
Figure 1: (a) Structure and (b) reactivity of B12.
Figure 2: (a) Schematic representation of B12 enzyme-involving systems. (b) Construction of biomimetic and bi...
Scheme 1: (a) Carbon-skeleton rearrangement mediated by a coenzyme B12-depenedent enzyme. (b) Electrochemical...
Scheme 2: Electrochemical carbon-skeleton arrangements mediated by B12 model complexes.
Figure 3: Key electrochemical reactivity of 1 and 2 in methylated forms.
Scheme 3: Carbon-skeleton arrangements mediated by B12-vesicle artificial enzymes.
Scheme 4: Carbon-skeleton arrangements mediated by B12-HSA artificial enzymes.
Scheme 5: Photochemical carbon-skeleton arrangements mediated by B12-Ru@MOF.
Scheme 6: (a) Methyl transfer reaction mediated by B12-dependent methionine synthase. (b) Methyl transfer rea...
Scheme 7: Methyl transfer reaction for the detoxification of inorganic arsenics.
Scheme 8: (a) Dechlorination of 1,1,2,2-tetrarchloroethene mediated by a reductive dehalogenase. (b) Electroc...
Scheme 9: Visible-light-driven dechlorination of DDT using 1 in the presence of photosensitizers.
Scheme 10: 1,2-Migration of a phenyl group mediated by the visible-light-driven catalytic system composed of 1...
Scheme 11: Ring-expansion reactions mediated by the B12-TiO2 hybrid catalyst with UV-light irradiation.
Scheme 12: Trifluoromethylation and perfluoroalkylation of aromatic compounds achieved through electrolysis wi...
Hydroarylations by cobalt-catalyzed C–H activation
- Rajagopal Santhoshkumar and
- Chien-Hong Cheng
Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202
- . The hydroarylation reaction further extended to pyrroles for selective monoalkenylation using [Cp*Co(CH3CN)3](SbF6)2 as the catalyst [55]. In contrast, branched-selective hydroarylation of terminal alkynes was achieved by Li et al. The addition of arenes 7 to propargyl alcohols, protected propargyl
- hydroarylation of glyoxylate with pyrimidine containing indoles and pyrroles 7 to provide products 63 with high productivity (Scheme 40) [79]. Similar to the imine, isocyanate is also an efficient electrophile for hydroarylation of C=N bond. It provides a high atom- and step-economical method for the preparation
Graphical Abstract
Scheme 1: Cobalt-catalyzed C–H carbonylation.
Scheme 2: Hydroarylation by C–H activation.
Scheme 3: Pathways for cobalt-catalyzed hydroarylations.
Scheme 4: Co-catalyzed hydroarylation of alkynes with azobenzenes.
Scheme 5: Co-catalyzed hydroarylation of alkynes with 2-arylpyridines.
Scheme 6: Co-catalyzed addition of azoles to alkynes.
Scheme 7: Co-catalyzed addition of indoles to alkynes.
Scheme 8: Co-catalyzed hydroarylation of alkynes with imines.
Scheme 9: A plausible pathway for Co-catalyzed hydroarylation of alkynes.
Scheme 10: Co-catalyzed anti-selective C–H addition to alkynes.
Scheme 11: Co(III)-catalyzed hydroarylation of alkynes with indoles.
Scheme 12: Co(III)-catalyzed branch-selective hydroarylation of alkynes.
Scheme 13: Co(III)-catalyzed hydroarylation of terminal alkynes with arenes.
Scheme 14: Co(III)-catalyzed hydroarylation of alkynes with amides.
Scheme 15: Co(III)-catalyzed C–H alkenylation of arenes.
Scheme 16: Co-catalyzed alkylation of substituted benzamides with alkenes.
Scheme 17: Co-catalyzed switchable hydroarylation of styrenes with 2-aryl pyridines.
Scheme 18: Co-catalyzed linear-selective hydroarylation of alkenes with imines.
Scheme 19: Co-catalyzed linearly-selective hydroarylation of alkenes with N–H imines.
Scheme 20: Co-catalyzed branched-selective hydroarylation of alkenes with imines.
Scheme 21: Mechanism of Co-catalyzed hydroarylation of alkenes.
Scheme 22: Co-catalyzed intramolecular hydroarylation of indoles.
Scheme 23: Co-catalyzed asymmetric hydroarylation of alkenes with indoles.
Scheme 24: Co-catalyzed hydroarylation of alkenes with heteroarenes.
Scheme 25: Co(III)-catalyzed hydroarylation of activated alkenes with 2-phenyl pyridines.
Scheme 26: Co(III)-catalyzed C–H alkylation of arenes.
Scheme 27: Co(III)-catalyzed C2-alkylation of indoles.
Scheme 28: Co(III)-catalyzed switchable hydroarylation of alkyl alkenes with indoles.
Scheme 29: Co(III)-catalyzed C2-allylation of indoles.
Scheme 30: Co(III)-catalyzed ortho C–H alkylation of arenes with maleimides.
Scheme 31: Co(III)-catalyzed hydroarylation of maleimides with arenes.
Scheme 32: Co(III)-catalyzed hydroarylation of allenes with arenes.
Scheme 33: Co-catalyzed hydroarylative cyclization of enynes with carbonyl compounds.
Scheme 34: Mechanism for the Co-catalyzed hydroarylative cyclization of enynes with carbonyl compounds.
Scheme 35: Co-catalyzed addition of 2-arylpyridines to aromatic aldimines.
Scheme 36: Co-catalyzed addition of 2-arylpyridines to aziridines.
Scheme 37: Co(III)-catalyzed hydroarylation of imines with arenes.
Scheme 38: Co(III)-catalyzed addition of arenes to ketenimines.
Scheme 39: Co(III)-catalyzed three-component coupling.
Scheme 40: Co(III)-catalyzed hydroarylation of aldehydes.
Scheme 41: Co(III)-catalyzed addition of arenes to isocyanates.
Investigation of the electrophilic reactivity of the biologically active marine sesquiterpenoid onchidal and model compounds
- Melissa M. Cadelis and
- Brent R. Copp
Beilstein J. Org. Chem. 2018, 14, 2229–2235, doi:10.3762/bjoc.14.197
- . Signals attributable to N-alkyl-3-substituted pyrroles 7–9 and N-pentylacetamide 10 [δH 7.62 t, J = 4.7 Hz; 2.28 m] were observed. Purification by silica gel column chromatography, eluting with CH2Cl2, afforded pyrrole adduct 7 as the free base. Elution with CH2Cl2/MeOH afforded two fractions with the
Graphical Abstract
Figure 1: Masked and unmasked 1,4-dialdehyde natural products 1–6.
Scheme 1: Products of the reaction of onchidal (6) with 1-pentylamine. Reagents and conditions: 1-pentylamine...
Scheme 2: Proposed mechanism for formation of onchidal diaminated adducts.
Figure 2: Target onchidal model compounds 11–18.
Scheme 3: Synthesis of n-pentyl dialdehydes 11 and 12 and enol acetate 13. Reagents and conditions: a) n-hexa...
Scheme 4: Synthesis of cyclohexylmethyl dialdehydes 15 and 16 and enol acetate 17. Reagents and conditions: a...
Figure 3: Pyrrole product 29 and salt 30 obtained from the reaction of dialdehyde 11 with n-pentylamine.
Scheme 5: Reaction of dialdehyde 11 with excess 1-pentylamine to form 29. Reagents and conditions: (a) 1-pent...
Figure 4: Pyrrole product 31 and salt 32 obtained from reaction of dialdehyde 15 with n-pentylamine.
Figure 5: Lysine adducts arising from the reaction of onchidal (6) with lysozyme.
Figure 6: SDS-PAGE separation of lysozyme after modification with 11 (left), 13 (middle), 15 (right).
Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry
- Michael K. Bogdos,
- Emmanuel Pinard and
- John A. Murphy
Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179
- reduction of aryl halides to the corresponding non-halogenated aromatics. This was extended to the coupling of aryl halides to a variety of substituted pyrroles, using N,N-bis(2,6-diisopropylphenyl)perylene-3,4,9,10-bis(dicarboximide) (PDI) as the photocatalyst, under blue LED irradiation, in DMSO and in
- protocol for coupling simple five-membered heterocycles to substituted benzenes, using Eosin Y as the photocatalyst, starting from arenediazonium salts (Scheme 6) [47]. The scope of the reaction is limited to N-Boc-pyrroles, furans and a couple of simple substituted thiophenes with respect to the
- molecules. An interesting report of C–N bond formation is seen in König and co-workers’ method for the formation of sulfonamidated pyrroles, using acridinium salts as photocatalysts, in the presence of oxygen and sodium hydroxide (Scheme 10) [53]. Unfortunately, this protocol was investigated for its use in
Graphical Abstract
Figure 1: Depiction of the energy levels of a typical organic molecule and the photophysical processes it can...
Figure 2: General catalytic cycle of a photocatalyst in a photoredox organocatalysed reaction. [cat] – photoc...
Figure 3: Structures and names of the most common photocatalysts encountered in the reviewed literature.
Figure 4: General example of a reductive quenching catalytic cycle. [cat] – photocatalyst, [cat]* – photocata...
Figure 5: General example of an oxidative quenching catalytic cycle. [cat] – photocatalyst, [cat]* – photocat...
Scheme 1: Oxidative coupling of aldehydes and amines to amides using acridinium salt photocatalysis.
Figure 6: Biologically active molecules containing a benzamide linkage.
Scheme 2: The photocatalytic reduction of amino acids to produce the corresponding free or protected amines.
Scheme 3: The organocatalysed photoredox base-mediated oxidation of thiols to disulfides.
Scheme 4: C-Terminal modification of peptides and proteins using organophotoredox catalysis.
Scheme 5: The reduction and aryl coupling of aryl halides using a doubly excited photocatalyst (PDI).
Figure 7: Mechanism for the coupling of aryl halides using PDI, which is excited sequentially by two photons.
Scheme 6: The arylation of five-membered heteroarenes using arenediazonium salts under organophotoredox condi...
Scheme 7: The C–H (hetero)arylation of five-membered heterocycles under Eosin Y photocatalysis.
Scheme 8: The C–H sulfurisation of imidazoheterocycles using Eosin B-catalyzed photochemical methods.
Scheme 9: The introduction of the thiocyanate group using Eosin Y photocatalysis.
Scheme 10: Sulfonamidation of pyrroles using oxygen as the terminal oxidant.
Scheme 11: DDQ-catalysed C–H amination of arenes and heteroarenes.
Scheme 12: Photoredox-promoted radical Michael addition reactions of allylic or benzylic carbons.
Figure 8: Proposed mechanistic rationale for the observed chemoselectivities.
Scheme 13: The photocatalytic manipulation of C–H bonds adjacent to amine groups.
Scheme 14: The perylene-catalysed organophotoredox tandem difluoromethylation–acetamidation of styrene-type al...
Figure 9: Examples of biologically active molecules containing highly functionalised five membered heterocycl...
Scheme 15: The [3 + 2]-cycloaddition leading to the formation of pyrroles, through the reaction of 2H-azirines...
Figure 10: Proposed intermediate that determines the regioselectivity of the reaction.
Figure 11: Comparison of possible pathways of reaction and various intermediates involved.
Scheme 16: The acridinium salt-catalysed formation of oxazoles from aldehydes and 2H-azirines.
Scheme 17: The synthesis of oxazolines and thiazolines from amides and thioamides using organocatalysed photor...
Figure 12: Biologically active molecules on the market containing 1,3,4-oxadiazole moieties.
Scheme 18: The synthesis of 1,3,4-oxadiazoles from aldehyde semicarbazones using Eosin Y organophotocatalysis.
Scheme 19: The dimerization of primary thioamides to 1,2,4-thiadiazoles catalysed by the presence of Eosin Y a...
Scheme 20: The radical cycloaddition of o-methylthioarenediazonium salts and substituted alkynes towards the f...
Scheme 21: The dehydrogenative cascade reaction for the synthesis of 5,6-benzofused heterocyclic systems.
Figure 13: Trifluoromethylated version of compounds which have known biological activities.
Scheme 22: Eosin Y-catalysed photoredox formation of 3-substituted benzimidazoles.
Scheme 23: Oxidation of dihydropyrimidines by atmospheric oxygen using photoredox catalysis.
Scheme 24: Photoredox-organocatalysed transformation of 2-substituted phenolic imines to benzoxazoles.
Scheme 25: Visible light-driven oxidative annulation of arylamidines.
Scheme 26: Methylene blue-photocatalysed direct C–H trifluoromethylation of heterocycles.
Scheme 27: Photoredox hydrotrifluoromethylation of terminal alkenes and alkynes.
Scheme 28: Trifluoromethylation and perfluoroalkylation of aromatics and heteroaromatics.
Scheme 29: The cooperative asymmetric and photoredox catalysis towards the functionalisation of α-amino sp3 C–...
Scheme 30: Organophotoredox-catalysed direct C–H amidation of aromatics.
Scheme 31: Direct C–H alkylation of heterocycles using BF3K salts. CFL – compact fluorescent lamp.
Figure 14: The modification of camptothecin, demonstrating the use of the Molander protocol in LSF.
Scheme 32: Direct C–H amination of aromatics using acridinium salts.
Scheme 33: Photoredox-catalysed nucleophilic aromatic substitution of nucleophiles onto methoxybenzene derivat...
Scheme 34: The direct C–H cyanation of aromatics with a focus on its use for LSF.
Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis
- Gwendal Grelier,
- Benjamin Darses and
- Philippe Dauban
Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128
- stereoselective trans iodo-benzoylation of glycals using a combination of IBX and molecular iodine, that is considered as a source of I+ formed from the in situ generated hypoiodite species [30]. The controlled oxidation of various N-(alkyl)- and N-(aryl)pyrroles with Dess–Martin periodinane also leads to
- issue of sustainability with polyvalent organoiodine reagents. Functionalization of ketones and alkenes with IBX. Functionalization of pyrroles with DMP. Catalytic benzoyloxy-trifluoromethylation reported by Szabó. Catalytic benzoyloxy-trifluoromethylation reported by Mideoka. Catalytic 1,4-benzoyloxy
Graphical Abstract
Scheme 1: Strategies to address the issue of sustainability with polyvalent organoiodine reagents.
Scheme 2: Functionalization of ketones and alkenes with IBX.
Scheme 3: Functionalization of pyrroles with DMP.
Scheme 4: Catalytic benzoyloxy-trifluoromethylation reported by Szabó.
Scheme 5: Catalytic benzoyloxy-trifluoromethylation reported by Mideoka.
Scheme 6: Catalytic 1,4-benzoyloxy-trifluoromethylation of dienes.
Scheme 7: Catalytic benzoyloxy-trifluoromethylation of allylamines.
Scheme 8: Catalytic benzoyloxy-trifluoromethylation of enynes.
Scheme 9: Catalytic benzoyloxy-trifluoromethylation of allenes.
Scheme 10: Alkynylation of N-(aryl)imines with EBX for the formation of furans.
Scheme 11: Catalytic benzoyloxy-alkynylation of diazo compounds.
Scheme 12: Catalytic asymmetric benzoyloxy-alkynylation of diazo compounds.
Scheme 13: Catalytic 1,2-benzoyloxy-azidation of alkenes.
Scheme 14: Catalytic 1,2-benzoyloxy-azidation of enamides.
Scheme 15: Catalytic 1,2-benzoyloxy-iodination of alkenes.
Scheme 16: Seminal study with cyclic diaryl-λ3-iodane.
Scheme 17: Synthesis of alkylidenefluorenes from cyclic diaryl-λ3-iodanes.
Scheme 18: Synthesis of alkyne-substituted alkylidenefluorenes.
Scheme 19: Synthesis of phenanthrenes from cyclic diaryl-λ3-iodanes.
Scheme 20: Synthesis of dibenzocarbazoles from cyclic diaryl-λ3-iodanes.
Scheme 21: Synthesis of triazolophenantridines from cyclic diaryl-λ3-iodanes.
Scheme 22: Synthesis of functionalized benzoxazoles from cyclic diaryl-λ3-iodanes.
Scheme 23: Sequential difunctionalization of cyclic diaryl-λ3-iodanes.
Scheme 24: Double Suzuki–Miyaura coupling reaction of cyclic diaryl-λ3-iodanes.
Scheme 25: Synthesis of a δ-carboline from cyclic diaryl-λ3-iodane.
Scheme 26: Synthesis of N-(aryl)carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 27: Synthesis of carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 28: Synthesis of carbazoles and acridines from cyclic diaryl-λ3-iodanes.
Scheme 29: Synthesis of dibenzothiophenes from cyclic diaryl-λ3-iodanes.
Scheme 30: Synthesis of various sulfur heterocycles from cyclic diaryl-λ3-iodanes.
Scheme 31: Synthesis of dibenzothioheterocycles from cyclic diaryl-λ3-iodanes.
Scheme 32: Synthesis of dibenzosulfides and dibenzoselenides from cyclic diaryl-λ3-iodanes.
Scheme 33: Synthesis of dibenzosulfones from cyclic diaryl-λ3-iodanes.
Scheme 34: Seminal study with linear diaryl-λ3-iodanes.
Scheme 35: N-Arylation of benzotriazole with symmetrical diaryl-λ3-iodanes.
Scheme 36: Tandem catalytic C–H/N–H arylation of indoles with diaryl-λ3-iodanes.
Scheme 37: Tandem N-arylation/C(sp2)–H arylation with diaryl-λ3-iodanes.
Scheme 38: Catalytic intermolecular diarylation of anilines with diaryl-λ3-iodanes.
Scheme 39: Catalytic synthesis of diarylsulfides with diaryl-λ3-iodanes.
Scheme 40: α-Arylation of enolates using [bis(trifluoroacetoxy)iodo]arenes.
Scheme 41: Mechanism of the α-arylation using [bis(trifluoroacetoxy)iodo]arene.
Scheme 42: Catalytic nitrene additions mediated by [bis(acyloxy)iodo]arenes.
Scheme 43: Tandem of C(sp3)–H amination/sila-Sonogashira–Hagihara coupling.
Scheme 44: Tandem reaction using a λ3-iodane as an oxidant, a substrate and a coupling partner.
Scheme 45: Synthesis of 1,2-diarylated acrylamidines with ArI(OAc)2.
Cross-coupling of dissimilar ketone enolates via enolonium species to afford non-symmetrical 1,4-diketones
- Keshaba N. Parida,
- Gulab K. Pathe,
- Shimon Maksymenko and
- Alex M. Szpilman
Beilstein J. Org. Chem. 2018, 14, 992–997, doi:10.3762/bjoc.14.84
- -membered heterocycles such as thiophenes, furans, and pyrroles. Consequently, numerous multistep approaches to unsymmetrical 1,4-dicarbonyl compounds involving, e.g., SN2-type displacements [1] or highly functionalized substrates such as β-ketoesters [2][3] or β-ketosulfones [4] have been developed
Graphical Abstract
Scheme 1: Oxidative intermolecular cross-coupling of dissimilar enolates.
Scheme 2: Scope of the homo- and heterocoupling of enolates. The purple bond indicates the bond formed. The b...
Scheme 3: Study of diastereoselectivity of the cross-coupling reaction.
