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Search for "platinum(II)" in Full Text gives 26 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones
- Ruben Manuel Figueira de Abreu,
- Peter Ehlers and
- Peter Langer
Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228
- attempt, we used platinum(II) chloride (PtCl2) as the Lewis acid and 4a as the model starting material. The reaction afforded a mixture of the desired product 5a and the starting material. Separation of both compounds proved to be difficult and, hence, optimisation was carried out as depicted in Table 1
Graphical Abstract
Figure 1: Synthesis of uracil-based alkynes and aryl structures [51,62-65].
Figure 2: Structures of uracil derivatives A, B, and C.
Scheme 1: Strategy for the synthesis of the cyclised product 5. Conditions: i) Br2 (2 equiv), Ac2O (1.5 equiv...
Scheme 2: Synthesis and isolated yields of 1,3-dimethyl-5-aryl-6-[2-(aryl)ethynyl]uracils 4a–i. Reaction cond...
Scheme 3: Scope and isolated yields of the synthesis of 5. Reaction conditions: 4 (1 equiv), p-TsOH·H2O (20 e...
Scheme 4: Proposed reaction mechanism of the cyclisation with N,N-dimethylanilino functional groups.
Figure 3: UV–vis absorption (left) and emission (right, λex = 400 nm) spectra of 5a, 5d, 5f, 5g, 5h, and 5i i...
Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis
- Prodip Howlader and
- Michael Schmittel
Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62
- ]. Using addition and removal of chloride, the Mirkin group reversibly and quantitatively toggled the platinum(II)-based switch 1262+ between a homo- and heteroligated form (Figure 29) [132]. In the closed platinum(II) complex 1262+, the urea units were available for activation of butenone (127) by
Graphical Abstract
Figure 1: Butterfly 1 (Figure was reprinted with permission from [45]. Copyright 2012 American Chemical Society. ...
Figure 2: Synthesis of the three-component heteroleptic molecular boat 8 and its use as a catalyst for the Kn...
Figure 3: Synthesis of the two-component triangle 14 and three-component heteroleptic prism 15 [59]. Figure was a...
Figure 4: Catalytic Michael addition reaction using the urea-decorated molecular prism 15 [59].
Figure 5: Self-assembly of two-component tetragonal prismatic architectures with different cavity size. Figur...
Figure 6: Construction of artificial LHS using rhodamine B as an acceptor and 24b as donor generating a photo...
Figure 7: Synthesis of supramolecular spheres with varying [AuCl] concentration inside the cavity. Figure was...
Figure 8: Hydroalkoxylation reaction of γ-allenol 34 in the presence of [AuCl]-encapsulated molecular spheres ...
Figure 9: Two-component heteroleptic triangles of different size containing a BINOL functionality. Figure was...
Figure 10: Asymmetric conjugate addition of chalcone 42 with trans-styrylboronic acid (43) catalyzed by BINOL-...
Figure 11: Encapsulation of monophosphoramidite-Rh(I) catalyst into a heteroleptic tetragonal prismatic cage 47...
Figure 12: (a) Representations of the basic HETPYP, HETPHEN, and HETTAP complex motifs. (b) The three-componen...
Figure 13: Two representative four-component rotors, with a (top) two-arm stator and (bottom) a four-arm stato...
Figure 14: Four-component rotors with a monohead rotator. Figure was adapted with permission from [94]. Copyright ...
Figure 15: (left) Click reaction catalyzed by rotors [Cu2(55)(60)(X)]2+. (right) Yield as a function of the ro...
Figure 16: A supramolecular AND gate. a) In truth table state (0,0) two nanoswitches serve as the receptor ens...
Figure 17: Two supramolecular double rotors (each has two rotational axes) and reference complex [Cu(78)]+ for...
Figure 18: The slider-on-deck system (82•X) (X = 83, 84, or 85). Figure is from [98] and was reprinted from the jo...
Figure 19: Catalysis of a conjugated addition reaction in the presence of the slider-on-deck system (82•X) (X ...
Figure 20: A rotating catalyst builds a catalytic machinery. For catalysis of the catalytic machinery, see Figure 21. F...
Figure 21: Catalytic machinery. Figure was adapted from [100] (“Evolution of catalytic machinery: three-component n...
Figure 22: An information system based on (re)shuffling components between supramolecular structures [99]. Figure ...
Figure 23: Switching between dimeric heteroleptic and homoleptic complex for OFF/ON catalytic formation of rot...
Figure 24: A chemically fueled catalytic system [112]. Figure was adapted from [112]. Copyright 2021 American Chemical S...
Figure 25: (Top) Operation of a fuel acid. (Bottom) Knoevenagel addition [112].
Figure 26: Development of the yield of Knoevenagel product 118 in a fueled system [112]. Figure was reprinted with ...
Figure 27: Weak-link strategy to increased catalytic activity in epoxide opening [119]. Figure was adapted from [24]. C...
Figure 28: A ON/OFF polymerization switch based on the weak-link approach [118]. Figure was reprinted with permissi...
Figure 29: A weak-link switch turning ON/OFF a Diels–Alder reaction [132]. Figure was reprinted with permission fro...
Figure 30: A catalyst duo allowing selective activation of one of two catalytic acylation reactions [133] upon subs...
Figure 31: A four-state switchable nanoswitch (redrawn from [134]).
Figure 32: Sequential catalysis as regulated by nanoswitch 138 and catalyst 139 in the presence of metal ions ...
Figure 33: Remote control of ON/OFF catalysis administrated by two nanoswitches through ion signaling (redrawn...
All-carbon [3 + 2] cycloaddition in natural product synthesis
- Zhuo Wang and
- Junyang Liu
Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251
- Iwasawa and co-workers in 2011 [18][66] (Scheme 10A). Treatment of Boc-protected aniline 139 and n-butyl vinyl ether (140) with a platinum(II) catalyst afforded tricyclic indole 141 in 83% yield. The authors suggested that this catalytic [3 + 2] cycloaddition reaction may involve an α,β-unsaturated
- reaction. Total synthesis of natural products reported by Yang and co-workers applying rhodium-catalyzed intramolecular [3 + 2] cycloaddition. (A) Synthesis of (−)-lingzhiol (17) [49]. (B) Synthesis of lycojaponicumin C (18) [58]. (C) Synthesis of sinensilactam A (20) [59]. (A) Platinum(II)-catalyzed
Graphical Abstract
Figure 1: Highly-substituted five-membered carbocycle in biologically significant natural products.
Figure 2: Natural product synthesis featuring the all-carbon [3 + 2] cycloaddition. (Quaternary carbon center...
Scheme 1: Representative natural product syntheses that feature the all-carbon [3 + 2] cyclization as the key...
Scheme 2: (A) An intramolecular trimethylenemethane diyl [3 + 2] cycloaddition with allenyl diazo compound 38...
Scheme 3: (A) Palladium-catalyzed intermolecular carboxylative TMM cycloaddition [36]. (B) The proposed mechanism....
Scheme 4: Natural product syntheses that make use of palladium-catalyzed intermolecular [3 + 2] cycloaddition...
Scheme 5: (A) Phosphine-catalyzed [3 + 2] cycloaddition [17]. (B) The proposed mechanism.
Scheme 6: Lu’s [3 + 2] cycloaddition in natural product synthesis. (A) Synthesis of longeracinphyllin A (10) [41]...
Scheme 7: (A) Phosphine-catalyzed [3 + 2] annulation of unsymmetric isoindigo 100 with allene in the preparat...
Scheme 8: (A) Rhodium-catalyzed intracmolecular [3 + 2] cycloaddition [49]. (B) The proposed catalytic cycle of t...
Scheme 9: Total synthesis of natural products reported by Yang and co-workers applying rhodium-catalyzed intr...
Scheme 10: (A) Platinum(II)-catalyzed intermolecular [3 + 2] cycloaddition of propargyl ether 139 and n-butyl ...
Scheme 11: (A) Platinum-catalyzed intramolecular [3 + 2] cycloaddition of propargylic ketal derivative 142 to ...
Scheme 12: (A) Synthesis of phyllocladanol (21) features a Lewis acid-catalyzed formal intramolecular [3 + 2] ...
Scheme 13: The recent advances of [3 + 2] annulation in natural product synthesis. (A) The preparation of melo...
A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand
- Matthias Hardy,
- Marianne Engeser and
- Arne Lützen
Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220
- (acetylide)platinum(II) complex [Pt(L1)2(PBu3)2] as a linear metalloligand. The reaction of this metalloligand with iron(II) cations and pyridine-2-carbaldehyde according to the subcomponent self-assembly approach yielded decanuclear heterobimetallic tetrahedron [Fe4Pt6(L2)12](OTf)8. Thus, combination of
- platinum(II) ions to be especially suitable to prepare a linear metalloligand due to their highly predictable square-planar coordination environment that can easily be employed to access tetravalent planar or divalent V-shaped cis- or linear trans-configurated complexes [43][44][45]. In this context
- platinum(II)-bis(acetylide) complexes [46][47] proved useful as building blocks for the construction of polymers [48], rings [49][50] and cages [36][42][51]. These neutral compounds are usually easy-to-access, rather stable and the cis- and trans-isomers can be separated efficiently. In this work we
Graphical Abstract
Scheme 1: Stepwise assembly of the heterobimetallic tetrahedron 4, starting from 4-ethynylaniline (1) and tra...
Figure 1: ESI(+) mass spectrum of heterobimetallic complex 4. The top inset shows the experimentally observed...
Figure 2: UV–vis spectrum of heterobimetallic complex 4 (1150 µM in acetonitrile at 295 K, 0.01 mm cuvette).
Figure 3: Schematic representation of symmetry-considerations concerning possible diastereomeric tetrahedra. ...
Figure 4: Detailed excerpt of the 31P NMR spectrum of 4 (202 MHz, acetonitrile-d3, 298 K).
Figure 5: 1H NMR and DOSY spectrum of heterobimetallic assembly 4 (500 MHz, acetonitilre-d3, 298 K).
Figure 6: GFN2-xTB minimized gas phase models of the cationic units of all possible diastereomers of 4. Color...
Photochromic diarylethene ligands featuring 2-(imidazol-2-yl)pyridine coordination site and their iron(II) complexes
- Andrey G. Lvov,
- Max Mörtel,
- Anton V. Yadykov,
- Frank W. Heinemann,
- Valerii Z. Shirinian and
- Marat M. Khusniyarov
Beilstein J. Org. Chem. 2019, 15, 2428–2437, doi:10.3762/bjoc.15.235
- their complexes with rhodium(I) [18], platinum(II) [30], and iridium(III) [31] were reported. In contrast, in our work, the 2-(imidazol-2-yl)pyridine unit is used as a heterocyclic moiety of diarylethenes with cyclopentenone, cyclopentene, and cyclohexenone ethene bridges. The novel ligands have been
Graphical Abstract
Figure 1: Families of diarylethene-bases ligands with spatial proximity of coordination site (blue) and photo...
Scheme 1: Synthesis of photochromic ligands.
Figure 2: Electronic spectra of diarylethene 6 upon UV irradiation (313 nm, toluene, c = 3.4 × 10−5 M). Inset...
Scheme 2: Reversible photocyclization of ligand 6.
Figure 3: Molecular structure of complexes 8 (top) and 9 (bottom) at 100 K. The H atoms are omitted for clari...
Figure 4: Variable temperature χT product (blue) and χ (green) of 8 (top) and 9 (bottom) measured at an exter...
2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes
- Li-Li Wang,
- Yi-Kuan Tu,
- Huan Yao and
- Wei Jiang
Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146
- sidewalls have been synthesized and characterized. The macrocycle containing isophthalamide bridges can bind square-planar chloride coordination complexes of gold(III), platinum(II), and palladium(II) in CDCl3, while the macrocycle with 2,6-pyridine dicarboxamide bridging units cannot. This may be due to
- a pair of new tetralactam macrocycles with 2,3-dibutoxynaphthalene as the sidewalls. The tetralactam macrocycle with 2,6-pyridine dicarboxamide cannot bind square-planar chloride coordination complexes of gold(III), platinum(II), and palladium(II) in CDCl3, while the macrocycle containing
- isophthalamide bridging units bind these complexes with decent binding affinities. This macrocycle shows similar binding affinity to chloride, weaker affinity to the chloride complex of gold(III), and much stronger affinities to the chloride complexes of platinum(II) and palladium(II), when compared to the
Graphical Abstract
Scheme 1: (a) Chemical structures of the reported tetralactam macrocycles with aromatic sidewalls; (b) synthe...
Figure 1: 1H NMR spectra (500 MHz, CDCl3) of a) 1 at 298 K, b) 1 at 223 K, and c) 2 at 298 K.
Figure 2: Two different views of the X-ray single crystal structure of 1 obtained from its CH3CN solution.
Figure 3: Partial 1H NMR spectra (500 MHz, CDCl3, 0.5 mM, 298 K) of 1 and the equimolar mixture with TBA[AuCl4...
Figure 4: ESI mass spectrum of complex AuCl4−@1.
Figure 5: Energy-minimized structure of a) AuCl4−@1 and b) AuCl4−@2 at the level of theory of PM3 by using Sp...
Figure 6: a) Fluorescence emission spectra of 1 (20 µM) upon addition of different amounts of TBA[AuCl4] (con...
Coordination-driven self-assembly of discrete Ru6–Pt6 prismatic cages
- Aderonke Ajibola Adeyemo and
- Partha Sarathi Mukherjee
Beilstein J. Org. Chem. 2018, 14, 2242–2249, doi:10.3762/bjoc.14.199
- –ruthenium(II) clips (1a(NO3)2 and 1b(NO3)2) and a tritopic platinum(II) metalloligand 2 has been performed in methanol at room temperature. The [3 + 2] hexanuclear cages 3a and 3b were isolated in good yields and characterized by well-known spectroscopic techniques including multinuclear NMR, mass
- heterometallic prismatic cages 3a and 3b obtained from the reaction of two arene–ruthenium(II) clips 1a and 1b and tritopic platinum(II) metalloligand 2 in methanol/chloroform mixture in 3:2 ratio (Scheme 1). Both cages were fully characterized by 1H, 31P, 195Pt, 1H,1H COSY, DOSY NMR, electrospray ionization
- All efforts to obtain single crystals of the prismatic cages were unsuccessful so far. Thus the structures of 3a and 3b were optimized to get insights into their structural features. The tritopic platinum(II) metalloligand was optimized using the B3LYP method while the heterometallic cage structures
Graphical Abstract
Scheme 1: Self-assembly of the heterometallic prismatic cages.
Scheme 2: Synthesis of the platinum metalloligand 2.
Figure 1: 1H NMR of 3b in CD3OD.
Figure 2: UV–vis spectra of the metalloligand 2 and heterometallic prismatic cages 3a and 3b in methanol (1.0...
Figure 3: ESIMS spectrum of 3a in methanol. Inset: experimentally observed isotopic distribution patterns of ...
Figure 4: Energy-minimized structure of heterometallic trigonal prismatic cage 3a. Hydrogen atoms are omitted...
Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules
- Hendrik V. Schröder and
- Christoph A. Schalley
Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190
- Figure 27b), donor–acceptor interactions and hydrogen bonding generate a neutral TTF dimer that is surrounded by cofacially oriented bipyridinium units [112]. The intertwined structure is locked by formation of platinum(II)–pyridine coordination bonds. Interestingly, the doubly interlocked catenane
Graphical Abstract
Figure 1: The two one-electron oxidation reactions of tetrathiafulvalene (TTF, 1) and the corresponding prope...
Figure 2: UV–vis spectra and photographs of TTF 2 in its three stable oxidation states (black line = 2, orang...
Figure 3: Structure and conformations of two TTF dimers in solution, the mixed-valence and the radical-cation...
Figure 4: (a) The isomerism problem of TTF. (b)–(d) Major synthetic breakthroughs for the construction of TTF...
Figure 5: (a) Host–guest equilibrium between π-electron-poor cyclophane 3 and different TTFs with their corre...
Figure 6: TTF complexes with different host molecules.
Figure 7: Stable TTF (a) radical-cation and (b) mixed-valence dimers in confined molecular spaces.
Figure 8: A “three-pole supramolecular switch”: Controlled by its oxidation state, TTF (1) jumps back and for...
Figure 9: Redox-controlled closing and opening motion of the artificial molecular lasso 12.
Figure 10: Graphical illustration how a non-degenerate TTF-based shuttle works under electrochemical operation....
Figure 11: The first TTF-based rotaxane 13.
Figure 12: A redox-switchable bistable molecular shuttle 14.
Figure 13: The redox-switchable cyclodextrin-based rotaxane 15.
Figure 14: The redox-switchable non-ionic rotaxane 16 with a pyromellitic diimide macrocycle.
Figure 15: The redox-switchable TTF rotaxane 17 based on a crown/ammonium binding motif.
Figure 16: Structure and operation of the electro- and photochemically switchable rotaxane 18 which acts as po...
Figure 17: (a) The redox-switchable rotaxane 19 with a donor–acceptor pair which is stable in five different s...
Figure 18: Schematic representation of a molecular electronic memory based on a bistable TTF-based rotaxane. (...
Figure 19: Schematic representation of bending motion of a microcantilever beam with gold surface induced by o...
Figure 20: TTF-dimer interactions in a redox-switchable tripodal [4]rotaxane 22.
Figure 21: (a) A molecular friction clutch 23 which can be operated by electrochemical stimuli. (b) Schematic ...
Figure 22: Fusion between rotaxane and catenane: a [3]rotacatenane 24 which can stabilize TTF dimers.
Figure 23: The first TTF-based catenane 25.
Figure 24: Electrochemically controlled circumrotation of the bistable catenane 26.
Figure 25: A tristable switch based on the redox-active [2]catenane 27 with three different stations.
Figure 26: Structure of catenane-functionalized MOF NU-1000 [108] with structural representation of subcomponents. ...
Figure 27: (a) [3]Catenanes 29 and 30 which can stabilize mixed-valence or radical-cation dimers of TTF. (b) S...
Recent advances in materials for organic light emitting diodes
- Eli Zysman-Colman
Beilstein J. Org. Chem. 2018, 14, 1944–1945, doi:10.3762/bjoc.14.168
- Cebrián and Matteo Mauro review the advances made in platinum(II) complexes for OLEDs [3]. Rebecca Pittkowski and Thomas Strassner report bright blue-to-blue-green phosphorescent platinum(II) complexes employing sterically bulky diketonate ancillary ligands [4]. In addition, Lin Gan et al. describe a new
Recent advances in phosphorescent platinum complexes for organic light-emitting diodes
- Cristina Cebrián and
- Matteo Mauro
Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124
- square planar platinum(II) complexes bearing π-conjugated chromophoric ligands playing a key role in such respect. In this contribution, the most recent and promising trends in the field of phosphorescent platinum complexes will be reviewed and discussed. In particular, the importance of proper molecular
- including photocatalysis [6], bio-imaging [7][8], and solar-energy conversion [9], just to cite a few. Thompson and Forrest reported in 1998 on the first example of a phosphorescent emitter, namely 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (Pt(OEP)), used as dopant for the fabrication of
- an efficient (external quantum efficiency, EQE, ca. 4%) OLED device [10]. Since that pioneering work, an impressive amount of research effort has been devoted in the last two decades to seeking for TMCs that display better device performances. In this respect, iridium(III) and platinum(II
Graphical Abstract
Figure 1: Molecular structure of neutral platinum(II) complex 1 bearing four monodentate ligands; cy = cycloh...
Figure 2: Chemical structure of the dinuclear Pt complexes 2a–b and 3 [20].
Figure 3: Molecular structure of platinum(II) complexes bearing isoquinolinylpyrazolates; dip = 2,6-diisoprop...
Figure 4: Selected neutral platinum(II) complexes featuring dianionic biazolate and neutral bipyridines [27].
Figure 5: Selected neutral platinum(II) complexes from bipyrazolate and carbene-based chelates [34,35].
Figure 6: Cyclometalated thiazol-2-ylidene platinum(II) complexes with different acetylacetonate ligands [37].
Figure 7: Neutral platinum(II) complexes 13–15 bearing azolate ligands [13].
Figure 8: Chemical structure of neutral platinum(II) complexes 16–18 bearing azine-pyrazolato bidentate ligan...
Figure 9: Molecular structure of carbene-containing cyclometallated alkynylplatinum(II) complexes 19–21 [41].
Figure 10: Chemical structure of platinum(II) complexes 22a–d bearing asymmetric C^N^N tridentate ligands [53].
Figure 11: Chemical structure of platinum(II) complexes 23 bearing bis-cyclometalating 2,6-dipyridylbenzene ty...
Figure 12: Molecular structure of dendritic carbazole-containing alkynyl-platinum(II) complexes 24a–d [62].
Figure 13: Molecular structure of bipolar alkynyl-platinum(II) complexes 25 bearing carbazole and electron-acc...
Figure 14: Molecular structures of neutral platinum(II) complexes comprising donor-acceptor alkynyls (26) or e...
Figure 15: Chemical structure of the asymmetric Pt(II) derivatives 28 bearing triazole and tetrazole moieties ...
Figure 16: Molecular structure of the tetradentate platinum complexes 29–32 bearing N^C^C^N and C^C^C^N ligand...
Figure 17: Chemical structure of the tetradentate Pt complexes 33–38 based on N^C^C^N-type of ligands [80-84].
Figure 18: Chemical structure of the macrocyclic tetradentate platinum complexes reported by Wang and co-worke...
Figure 19: Molecular structure of complex 41–46 [88,89].
Figure 20: Molecular structure of asymmetric derivatives 47–49 based on triaryl-type of bridge [90].
Figure 21: Chemical structure of the asymmetric tetradentate derivatives 50 and 51 based on spirofluorene link...
Figure 22: Molecular structure of the pyridylazolate-based complexes 52–54 reported by Chi and co-workers [97].
Figure 23: Chemical structure of the red-to-NIR emitting complexes 55–57 bearing donor–acceptor triphenylamino...
Figure 24: Molecular structures of the Pt(IV) derivatives 58 and 59 employed as triplet emitters in solution-p...
Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands
- Rebecca Pittkowski and
- Thomas Strassner
Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54
- Rebecca Pittkowski Thomas Strassner Physical Organic Chemistry, Technische Universität Dresden, Bergstraße, 01069 Dresden, Germany 10.3762/bjoc.14.54 Abstract Luminescent organometallic platinum(II) compounds are of interest as phosphors for organic light emitting devices. Their emissive
- β-diketonates on the emission properties of C^C* cyclometalated complexes, employing the unsubstituted methyl-phenyl-imidazolium ligand. The quantum yield was significantly enhanced by changing the auxiliary ligand from acetylacetonate, where the corresponding platinum(II) complex shows only a very
- weak emission, to mesityl (mes) or duryl (dur) substituted acetylacetonates. The new complexes show very efficient emission with quantum yields >70% in the sky-blue spectral region (480 nm) and short decay times (<3 μs). Keywords: ancillary ligand; β-diketonates; photoluminescence; platinum(II
Graphical Abstract
Scheme 1: Synthesis of complexes 2 and 3.
Figure 1: ORTEP representation of 3. Thermal ellipsoids are drawn at the 50% probability level. Selected bond...
Figure 2: UV–vis absorption spectra of complexes 2 and 3 measured in dichloromethane at room temperature.
Figure 3: Emission spectra of complexes 2 and 3 measured at room temperature and 77 K, 2 wt % in a PMMA matri...
Figure 4: Cyclic voltammograms of complexes 2 and 3, analyte concentration 10−4 M. Measured in DMF (0.1 M TBA...
Figure 5: Thin films of Pt(MPIM)(acac) left, Pt(MPIM)(mes) (2) middle, and Pt(MPIM)(dur) (3) right, 2 wt % in...
Figure 6: Photoluminescence spectra of 2 and 3 compared to the emission profile of Pt(MPIM)(acac), 2 wt % in ...
Figure 7: Localization of spin density on the complexes Pt(MPIM)(acac) left, Pt(MPIM)(mes) (2) middle, and Pt...
Mannich base-connected syntheses mediated by ortho-quinone methides
- Petra Barta,
- Ferenc Fülöp and
- István Szatmári
Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43
- –platinum(II) complexes [94]. Both DNA binding and topoisomerase I inhibition studies proved that the coordination and stabilization of the quinone methide structure can effect marked changes in DNA reactivity. In a recent publication, 3-(aminomethyl)naphthoquinones were investigated from the point of view
Graphical Abstract
Scheme 1: Formation of amidoalkylnaphthols 4 via o-QM intermediate 3.
Scheme 2: Asymmetric syntheses of triarylmethanes starting from diarylmethylamines.
Scheme 3: Proposed mechanism for the formation of 2,2-dialkyl-3-dialkylamino-2,3-dihydro-1H-naphtho[2,1-b]pyr...
Scheme 4: Cycloadditions of isoflavonoid-derived o-QMs and various dienophiles.
Scheme 5: [4 + 2] Cycloaddition reactions between aminonaphthols and cyclic amines.
Scheme 6: Brønsted acid-catalysed reaction between aza-o-QMs and 2- or 3-substituted indoles.
Scheme 7: Formation of 3-(α,α-diarylmethyl)indoles 52 in different synthetic pathways.
Scheme 8: Alkylation of o-QMs with N-, O- or S-nucleophiles.
Scheme 9: Formation of DNA linkers and o-QM mediated polymers.
From dipivaloylketene to tetraoxaadamantanes
- Gert Kollenz and
- Curt Wentrup
Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1
- and ethyl esters were determined by X-ray crystallography [19]. The X-ray structure of the Pt(II) chelate of tetramethyl 2,6,9-trioxabicyclo[3.3.1]nona-3,7-diene obtained from tris-acetylacetonato platinum(II) was determined previously [22][23], and the separation of the enantiomers of the free ligand
Graphical Abstract
Scheme 1: Synthetic routes to 2,4,6,8-tetraoxaadamantanes.
Scheme 2: Conversion of dipivaloylketene (2) to bisdioxines (2,6,9-trioxabicyclo[3.3.1]nona-3,7-dienes) 4 and...
Scheme 3: 2,6,9-Trioxabicyclo[3.3.1]nonadienes (bisdioxines, 9–13) derived from dipivaloylketene (2).
Scheme 4: Mechanisms of formation of bisdioxine acid derivatives from dimer 3.
Scheme 5: Recently reported synthesis of chromenobisdioxines.
Scheme 6: Formation of tetraoxaadamantanes.
Scheme 7: Decarboxylative hydrolysis and oxa-Michael-type ring closure.
Scheme 8: Oxime and hydrazine derivatives of bisdioxines and tetraoxaadamantanes.
Figure 1: Bistetraoxaadamantane derivatives.
Scheme 9: Inward-pointing isocyanate, urethane and carbamate groups in bisdioxines. The diisocyanate is obtai...
Scheme 10: Microwave-assisted tetraoxaadamantane formation.
Scheme 11: Cyclic bisdioxine ester derivative 34 forming a single mono-tetraoxaadamantane.
Figure 2: Cyclic bisdioxine derivative not forming a tetraoxaadamantane due to reduced cavity size.
Figure 3: The bisdioxine-calix[6]arene derivative 37 complexes Cs+ but does not form a tetraoxaadamantane der...
Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds
- M. Fernanda N. N. Carvalho,
- Rudolf Herrmann and
- Gabriele Wagner
Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122
- platinum(II). The formed product structures depend not only on the reagents used but also on the substituents attached to the triple bonds. Cycloisomerisations with perfect atom economy lead to polycyclic heterocycles that resemble to some extent the AB ring system of paclitaxel. Herein, we present
- intermediate in the sulphur-reduction step of the cascade reaction, and the isolated product thus supports our mechanistic considerations. Platinum(II) catalysis applied to camphor-derived dialkynes with two different substituents can thus not only give valuable insight in the mechanism of such
Graphical Abstract
Scheme 1: Synthesis of 3-oxo-camphorsulfonylimine (3) [13,15] and its bis-alkynyl derivatives 4 from camphor-10-sulf...
Scheme 2: Reactions of bis-alkynyl camphor derivative 4a with TiCl4 and with Br2, respectively.
Scheme 3: Reactions of bis-alkynylcamphor derivatives 4a–e with catalytic amounts of PtCl2(PhCN)2.
Scheme 4: Attempted selective synthesis of 3-alkynyl derivatives via sulfonylimine reduction of oxoimide 3.
Scheme 5: Selective synthesis of 2-alkynyl derivatives by protection of the 3-oxo group as an acetal.
Scheme 6: Selective synthesis of 2-alkynyl derivatives by protection of the 3-oxo group as an imine.
Scheme 7: Synthesis of the bis-alkynyl derivatives bearing different alkyne substituents and their platinum-c...
Scheme 8: Proposed mechanism of the platinum-catalysed cycloisomerisation.
Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols
- Katrina Tait,
- Oday Alrifai,
- Rebecca Boutin,
- Jamie Haner and
- William Tam
Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209
- (Table 1, entry 13) along with the use of a platinum(II) catalyst (Table 1, entry 14). Using an anionic platinum(II) catalyst yielded substituted naphthalene 11a in a 22% yield, though this was considerably lower when compared to the optimized palladium catalyst. A variety of solvents were next screened
Graphical Abstract
Scheme 1: Various chemical transformations of 7-oxabenzonorbornadiene 1.
Scheme 2: Nucleophilic ring-opening reactions of 7-oxabenzonorbornadiene 1.
Scheme 3: Preparation of cyclopropanated 8 and its proposed ring-opening mechanisms.
Scheme 4: Formation of the possible regioisomers for the ring opening of asymmetric C1-substituted cyclopropa...
Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation
- Jie Wang,
- Zhiqiang Qiu,
- Yiming Wang,
- Li Li,
- Xuhong Guo,
- Duc-Truc Pham,
- Stephen F. Lincoln and
- Robert K. Prud’homme
Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7
- ]. In the first stage, the two chloro ligands on the four-coordinate square-planar platinum(II) center of cisplatin are displaced by PEG-b-PAA carboxylate groups to produce PEG-b-PAA-cisplatin micelles. Addition of α-CD results in host–guest complexation of the PEG segments of PEG-b-PAA and subsequent
Graphical Abstract
Figure 1: Structures of α-, β- and γ-CD. Individual carbon atom numbering is shown for one D-glucopyranose su...
Figure 2: Associations of hydrophobic substituents (circled) (a) and their disruption through host–guest comp...
Figure 3: Decrease of aqueous solution viscosity at a shear rate of 50 s−1 due to α-CD (circles), β-CD (recta...
Figure 4: The effect of (a) α-CD, (b) β-CD and (c) γ-CD on the hydrophobic interactions between n-C18H37 subs...
Figure 5: The effect of SDS addition on viscosity shear rate dependence for 2 wt % aqueous PAAodn solutions c...
Figure 6: Host–guest complexation between polymers with cyclodextrin and hydrophobic substituents.
Figure 7: Variation of viscosity with mole ratio of CD substituents to hydrophobic substituents on poly(acryl...
Figure 8: Illustration of the competitive intermolecular host–guest complexation of either the adamantyl subs...
Figure 9: Competitive host–guest complexations in which either the adamantyl substituent (red) or the n-hexyl...
Figure 10: (a) Substituted chitosan in which acyl- and adamantyl-substitution is 5% and 12 %, respectively. (b...
Figure 11: The formation of a AD-PEG micelle followed by the formation of a AD-PEG/α-CD supramolecular hydroge...
Figure 12: Interaction of PEG-b-PAA block copolymer with cis-diamminedichloroplatinum(II), cisplatin, to form ...
Figure 13: Solution to hydrogel transitions (a)–(d) for a PAAddn segment in the presence of competitive photo-...
Figure 14: Structures of the poly(acrylate)-based polymers PAAAzo (trans), PAAAzo (cis), PAA3α-CD and PAA6α-CD...
Figure 15: Variation of viscosity of a PAA6α-CD/PAAAzo solution (circles) and a PAA3α-CD/PAAAzo solution (tria...
Figure 16: The structures proposed for the poly(ethylene glycol)-b-poly(ethylamine)-g-dextran·γ-CD, PEG-PEI-de...
Figure 17: Structure of poly(ethylene glycol) polyrotaxane with adamantyl end substituents, and its temperatur...
Figure 18: Copolymers of either (a) N,N-dimethylacrylamide (DMAA) or (b) N-isopropylacrylamine (NIPAAM) with 1...
Figure 19: The copolymer of isopropylacrylamine and methacrylated β-CD (a) and its complexation of the anions ...
Figure 20: Solution to hydrogel transitions for two segments of PAAddn in the presence of β-CD and change in t...
Figure 21: Preparation of a β-CD and adamantyl substituted acrylamide polymer hydrogel involving host–guest co...
Figure 22: Aqueous solutions of the polymers poly-β-CD and poly-α-BrNP form the poly-β-CD/poly-α-BrNP hydrogel ...
Figure 23: (a) Randomly β-CD substituted poly(acrylate), PAA-6β-CD. (b) Randomly ferrocenyl substituted poly(a...
Figure 24: (a) The β-CD, adamantyl and ferrocenyl substituted pAAm and pNiPAAM polymers. (b) The β-CD, adamant...
Selected synthetic strategies to cyclophanes
- Sambasivarao Kotha,
- Mukesh E. Shirbhate and
- Gopalkrushna T. Waghule
Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142
- followed by cross metathesis. The molecule shows a hypsochromic shift which indicates rigidity in the molecule compared with the other linear molecules. Enyne metathesis: In 1998, Fürstner and co-workers [147] have employed platinum(II)-catalyzed enyne metathesis as a key step to form cyclophane ring
Graphical Abstract
Figure 1: General representation of cyclophanes.
Figure 2: cyclophanes one or more with heteroatom.
Figure 3: Metathesis catalysts 12–17 and C–C coupling catalyst 18.
Figure 4: Natural products containing the cyclophane skeleton.
Figure 5: Turriane family of natural products.
Scheme 1: Synthesis of [3]ferrocenophanes through Mannich reaction. Reagents and conditions: (i) excess HNMe2...
Scheme 2: Synthesis of cyclophanes through Michael addition. Reagents and conditions: (i) xylylene dibromide,...
Scheme 3: Synthesis of normuscopyridine analogue 37 through an oxymercuration–oxidation strategy. Reagents an...
Scheme 4: Synthesis of tribenzocyclotriyne 39 through Castro–Stephens coupling reaction. Reagents and conditi...
Scheme 5: Synthesis of cyclophane 43 through Glaser–Eglinton coupling. Reagents and conditions: (i) 9,10-bis(...
Scheme 6: Synthesis of the macrocyclic C-glycosyl cyclophane through Glaser coupling. Reagents and conditions...
Scheme 7: Synthesis of cyclophane-containing complex 49 through Glaser–Eglinton coupling reaction. Reagents a...
Scheme 8: Synthesis of cyclophane 53 through Glaser–Eglinton coupling. Reagents and conditions: (i) K2CO3, ac...
Figure 6: Cyclophanes 54–56 that have been synthesized through Glaser–Eglinton coupling.
Figure 7: Synthesis of tetrasubstituted [2.2]paracyclophane 57 and chiral cyclophyne 58 through Eglinton coup...
Scheme 9: Synthesis of cyclophane through Glaser–Hay coupling reaction. Reagents and conditions: (i) CuCl2 (1...
Scheme 10: Synthesis of seco-C/D ring analogs of ergot alkaloids through intramolecular Heck reaction. Reagent...
Scheme 11: Synthesis of muscopyridine 73 via Kumada coupling. Reagents and conditions: (i) 72, THF, ether, 20 ...
Scheme 12: Synthesis of the cyclophane 79 via McMurry coupling. Reagents and conditions: (i) 75, decaline, ref...
Scheme 13: Synthesis of stilbenophane 81 via McMurry coupling. Reagents and conditions: (i) TiCl4, Zn, pyridin...
Scheme 14: Synthesis of stilbenophane 85 via McMurry coupling. Reagents and conditions: (i) NBS (2 equiv), ben...
Figure 8: List of cyclophanes prepared via McMurry coupling reaction as a key step.
Scheme 15: Synthesis of paracyclophane by cross coupling involving Pd(0) catalyst. Reagents and conditions: (i...
Scheme 16: Synthesis of the cyclophane 112 via the pinacol coupling and 113 by RCM. Reagents and conditions: (...
Scheme 17: Synthesis of cyclophane derivatives 122a–c via Sonogoshira coupling. Reagents and conditions: (i) C...
Scheme 18: Synthesis of cyclophane 130 via Suzuki–Miyaura reaction as a key step. Reagents and conditions: (i)...
Scheme 19: Synthesis of the mycocyclosin via Suzuki–Miyaura cross coupling. Reagents and conditions: (i) benzy...
Scheme 20: Synthesis of cyclophanes via Wurtz coupling reaction Reagents and conditions: (i) PhLi, Et2O, C6H6,...
Scheme 21: Synthesis of non-natural glycophanes using alkyne metathesis. Reagents and conditions: (i) G-I (12)...
Figure 9: Synthesis of cyclophanes via ring-closing alkyne metathesis.
Scheme 22: Synthesis of crownophanes by cross-enyne metathesis. Reagents and conditions: (i) G-II (13), 5 mol ...
Scheme 23: Synthesis of (−)-cylindrocyclophanes A (156) and (−)-cylindrocyclophanes F (155). Reagents and cond...
Scheme 24: Synthesis of cyclophane 159 derivatives via SM cross-coupling and RCM. Reagents and conditions: (i)...
Scheme 25: Sexithiophene synthesis via cross metathesis. Reagents and conditions: (i) 161, Pd(PPh3)4, K2CO3, T...
Scheme 26: Synthesis of pyrrole-based cyclophane using enyne metathesis. Reagents and conditions: (i) Se, chlo...
Scheme 27: Synthesis of macrocyclic derivatives by RCM. Reagents and conditions: (i) G-I/G-II, CH2Cl2, 0.005 M...
Scheme 28: Synthesis of enantiopure β-lactam-based dienyl bis(dihydrofuran) 179. Reagents and conditions: (i) ...
Scheme 29: Synthesis of a [1.1.6]metaparacyclophane derivative 183 via SM cross coupling. Reagents and conditi...
Scheme 30: Synthesis of a [1.1.6]metaparacyclophane derivative 190 via SM cross coupling. Reagents and conditi...
Scheme 31: Template-promoted synthesis of cyclophanes involving RCM. Reagents and conditions: (i) acenaphthene...
Scheme 32: Synthesis of [3.4]cyclophane derivatives 200 via SM cross coupling and RCM. Reagents and conditions...
Figure 10: Examples for cyclophanes synthesized by RCM.
Scheme 33: Synthesis of the longithorone C framework assisted by fluorinated auxiliaries. Reagents and conditi...
Scheme 34: Synthesis of the longithorone framework via RCM. Reagents and conditions: (i) 213, NaH, THF, rt, 10...
Scheme 35: Synthesis of floresolide B via RCM as a key step. Reagents and conditions: (i) G-II (13, 0.1 equiv)...
Scheme 36: Synthesis of normuscopyridine (223) by the RCM strategy. Reagents and condition: (i) Mg, THF, hexen...
Scheme 37: Synthesis of muscopyridine (73) via RCM. Reagents and conditions: (i) 225, NaH, THF, 0 °C to rt, 1....
Scheme 38: Synthesis of muscopyridine (73) via RCM strategy. Reagents and conditions: (i) NaH, n-BuLi, 5-bromo...
Scheme 39: Synthesis of pyridinophane derivatives 223 and 245. Reagents and conditions: (i) PhSO2Na, TBAB, CH3...
Scheme 40: Synthesis of metacyclophane derivatives 251 and 253. Reagents and conditions: (i) 240, NaH, THF, rt...
Scheme 41: Synthesis of normuscopyridine and its higher analogues. Reagents and conditions: (i) alkenyl bromid...
Scheme 42: Synthesis of fluorinated ferrocenophane 263 via a [2 + 2] cycloaddition. Reagents and conditions: (...
Scheme 43: Synthesis of [2.n]metacyclophanes 270 via a [2 + 2] cycloaddition. Reagents and conditions: (i) Ac2...
Scheme 44: Synthesis of metacyclophane 273 by a [2 + 2 + 2] co-trimerization. Reagents and conditions: (i) [Rh...
Scheme 45: Synthesis of paracyclophane 276 via a [2 + 2 + 2] cycloaddition reaction. Reagents and conditions: ...
Scheme 46: Synthesis of cyclophane 278 via a [2 + 2 + 2] cycloaddition reaction. Reagents and conditions: (i) ...
Scheme 47: Synthesis of cyclophane 280 via a [2 + 2 + 2] cycloaddition. Reagents and conditions: (i) [(Rh(cod)(...
Scheme 48: Synthesis of taxane framework by a [2 + 2 + 2] cycloaddition. Reagents and conditions: (i) Cp(CO)2 ...
Scheme 49: Synthesis of cyclophane 284 and 285 via a [2 + 2 + 2] cycloaddition reaction. Reagents and conditio...
Scheme 50: Synthesis of pyridinophanes 293a,b and 294a,b via a [2 + 2 + 2] cycloaddition. Reagents and conditi...
Scheme 51: Synthesis of pyridinophanes 296 and 297 via a [2 + 2 + 2] cycloaddition. Reagents and conditions: (...
Scheme 52: Synthesis of triazolophane by a 1,3-dipolar cycloaddition. Reagents and conditions: (i) propargyl b...
Scheme 53: Synthesis of glycotriazolophane 309 by a click reaction. Reagents and conditions: (i) LiOH, H2O, Me...
Figure 11: Cyclophanes 310 and 311 prepared via click chemistry.
Scheme 54: Synthesis of cyclophane via the Dötz benzannulation. Reagents and conditions: (i) THF, 100 °C, 12 h...
Scheme 55: Synthesis of [6,6]metacyclophane by a Dötz benzannulation. Reagents and conditions: (i) THF, 100 °C...
Scheme 56: Synthesis of cyclophanes by a Dötz benzannulation. Reagents and conditions: (i) THF, 65 °C, 3 h; (i...
Scheme 57: Synthesis of muscopyridine (73) via an intramolecular DA reaction of ketene. Reagents and condition...
Scheme 58: Synthesis of bis[10]paracyclophane 336 via Diels–Alder reaction. Reagents and conditions: (i) DMAD,...
Scheme 59: Synthesis of [8]paracyclophane via DA reaction. Reagents and conditions: (i) maleic anhydride, 3–5 ...
Scheme 60: Biomimetic synthesis of (−)-longithorone A. Reagents and conditions: (i) Me2AlCl, CH2Cl2, −20 °C, 7...
Scheme 61: Synthesis of sporolide B (349) via a [4 + 2] cycloaddition reaction. Reagents and conditions: (i) P...
Scheme 62: Synthesis of the framework of (+)-cavicularin (352) via a [4 + 2] cycloaddition. Reagents and condi...
Scheme 63: Synthesis of oxazole-containing cyclophane 354 via Beckmann rearrangement. Reagents and conditions:...
Scheme 64: Synthesis of cyclophanes 360a–c via benzidine rearrangement. Reagents and conditions: (i) 356a–d, K2...
Scheme 65: Synthesis of cyclophanes 365a–c via benzidine rearrangement. Reagents and conditions: (i) BocNHNH2,...
Scheme 66: Synthesis of metacyclophane 367 via Ciamician–Dennstedt rearrangement. Reagents and conditions: (i)...
Scheme 67: Synthesis of cyclophane by tandem Claisen rearrangement and RCM as key steps. Reagents and conditio...
Scheme 68: Synthesis of cyclophane derivative 380. Reagents and conditions: (i) K2CO3, CH3CN, allyl bromide, r...
Scheme 69: Synthesis of metacyclophane via Cope rearrangement. Reagents and conditions: (i) MeOH, NaBH4, rt, 1...
Scheme 70: Synthesis of cyclopropanophane via Favorskii rearrangement. Reagents and conditions: (i) Br2, CH2Cl2...
Scheme 71: Cyclophane 389 synthesis via photo-Fries rearrangement. Reagents and conditions: (i) DMAP, EDCl/CHCl...
Scheme 72: Synthesis of normuscopyridine (223) via Schmidt rearrangement. Reagents and conditions: (i) ethyl s...
Scheme 73: Synthesis of crownophanes by tandem Claisen rearrangement. Reagents and conditions: (i) diamine, Et3...
Scheme 74: Attempted synthesis of cyclophanes via tandem Claisen rearrangement and RCM. Reagents and condition...
Scheme 75: Synthesis of muscopyridine via alkylation with 2,6-dimethylpyridine anion. Reagents and conditions:...
Scheme 76: Synthesis of cyclophane via Friedel–Craft acylation. Reagents and conditions: (i) CS2, AlCl3, 7 d, ...
Scheme 77: Pyridinophane 418 synthesis via Friedel–Craft acylation. Reagents and conditions: (i) 416, AlCl3, CH...
Scheme 78: Cyclophane synthesis involving the Kotha–Schölkopf reagent 421. Reagents and conditions: (i) NBS, A...
Scheme 79: Cyclophane synthesis involving the Kotha–Schölkopf reagent 421. Reagents and conditions: (i) BEMP, ...
Scheme 80: Cyclophane synthesis by coupling with TosMIC. Reagents and conditions: (i) (a) ClCH2OCH3, TiCl4, CS2...
Scheme 81: Synthesis of diaza[32]cyclophanes and triaza[33]cyclophanes. Reagents and conditions: (i) DMF, NaH,...
Scheme 82: Synthesis of cyclophane 439 via acyloin condensation. Reagents and conditions: (i) Na, xylene, 75%;...
Scheme 83: Synthesis of multibridged binuclear cyclophane 442 by aldol condensation. Reagents and conditions: ...
Scheme 84: Synthesis of various macrolactones. Reagents and conditions: (i) iPr2EtN, DMF, 77–83%; (ii) TBDMSCl...
Scheme 85: Synthesis of muscone and muscopyridine via Yamaguchi esterification. Reagents and conditions: (i) 4...
Scheme 86: Synthesis of [5]metacyclophane via a double elimination reaction. Reagents and conditions: (i) LiBr...
Figure 12: Cyclophanes 466–472 synthesized via Hofmann elimination.
Scheme 87: Synthesis of cryptophane via Baylis–Hillman reaction. Reagents and conditions: (i) methyl acrylate,...
Scheme 88: Synthesis of cyclophane 479 via double Chichibabin reaction. Reagents and conditions: (i) excess 478...
Scheme 89: Synthesis of cyclophane 483 via double Chichibabin reaction. Reagents and conditions: (i) 481, OH−;...
Scheme 90: Synthesis of cyclopeptide via an intramolecular SNAr reaction. Reagents and conditions: (i) TBAF, T...
Scheme 91: Synthesis of muscopyridine (73) via C-zip ring enlargement reaction. Reagents and conditions: (i) H...
Figure 13: Mechanism of the formation of compound 494.
Scheme 92: Synthesis of indolophanetetraynes 501a,b using the Nicholas reaction as a key step. Reagents and co...
Scheme 93: Synthesis of cyclophane via radical cyclization. Reagents and conditions: (i) cyclododecanone, phen...
Scheme 94: Synthesis of (−)-cylindrocyclophanes A (156) and (−)-cylindrocyclophanes F (155). Reagents and cond...
Scheme 95: Cyclophane synthesis via Wittig reaction. Reagents and conditions: (i) LiOEt (2.1 equiv), THF, −78 ...
Figure 14: Representative examples of cyclophanes synthesized via Wittig reaction.
Scheme 96: Synthesis of the [6]paracyclophane via isomerization of Dewar benzene. Reagents and conditions: (i)...
Come-back of phenanthridine and phenanthridinium derivatives in the 21st century
- Lidija-Marija Tumir,
- Marijana Radić Stojković and
- Ivo Piantanida
Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312
- combined with moieties covalently interacting with DNA and RNA. One of the most promising examples reported recently revealed that in a series of mono functional, cationic platinum(II) compounds, phenanthriplatin displayed a greater cytotoxic activity than either cisplatin or oxaliplatin despite a fact
Graphical Abstract
Scheme 1: The Grignard-based synthesis of 6-alkyl phenanthridine.
Scheme 2: Radical-mediated synthesis of 6-arylphenanthridine [14].
Scheme 3: A t-BuO• radical-assisted homolytic aromatic substitution mechanism proposed for the conversion of ...
Scheme 4: Synthesis of 5,6-unsubstituted phenanthridine starting from 2-iodobenzyl chloride and aniline [17].
Scheme 5: Phenanthridine synthesis initiated by UV-light irradiation photolysis of acetophenone O-ethoxycarbo...
Scheme 6: PhI(OAc)2-mediated oxidative cyclization of 2-isocyanobiphenyls with CF3SiMe3 [19,20].
Scheme 7: Targeting 6-perfluoroalkylphenanthridines [21,22].
Scheme 8: Easily accessible biphenyl isocyanides reacting under mild conditions (room temp., visible light ir...
Scheme 9: Microwave irradiation of Diels–Alder adduct followed by UV irradiation of dihydrophenanthridines yi...
Scheme 10: A representative palladium catalytic cycle.
Scheme 11: The common Pd-catalyst for the biphenyl conjugation results simultaneously in picolinamide-directed...
Scheme 12: Pd(0)-mediated cyclisation of imidoyl-selenides forming 6-arylphenanthridine derivatives [16]. The inse...
Scheme 13: Palladium-catalysed phenanthridine synthesis.
Scheme 14: Aerobic domino Suzuki coupling combined with Michael addition reaction in the presence of a Pd(OAc)2...
Scheme 15: Rhodium-catalysed alkyne [2 + 2 + 2] cycloaddition reactions [36].
Scheme 16: The O-acetyloximes derived from 2′-arylacetophenones underwent N–O bond cleavage and intramolecular ...
Scheme 17: C–H arylation with aryl chloride in the presence of a simple diol complex with KOt-Bu (top) [39]; for s...
Scheme 18: The subsequent aza-Claisen rearrangement, ring-closing enyne metathesis and Diels–Alder reaction – ...
Scheme 19: Phenanthridine central-ring cyclisation with simultaneous radical-driven phosphorylation [42].
Scheme 20: Three component reaction yielding the benzo[a]phenanthridine core in excellent yields [44].
Scheme 21: a) Reaction of malononitrile and 1,3-indandione with BEP to form the cyclised DPP products; b) pH c...
Figure 1: Schematic presentation of the intercalative binding mode by the neighbour exclusion principle and i...
Figure 2: Urea and guanidine derivatives of EB with modified DNA interactions [57].
Figure 3: Structure of mono- (3) and bis-biguanide (4) derivative. Fluorescence (y-axis normalised to startin...
Scheme 22: Bis-phenanthridinium derivatives (5–7; inert aliphatic linkers, R = –(CH2)4– or –(CH2)6–): rigidity...
Figure 4: Series of amino acid–phenanthridine building blocks (general structure 10; R = H; Gly) and peptide-...
Figure 5: General structure of 45 bis-ethidium bromide analogues. Reproduced with permission from [69]. Copyright...
Scheme 23: Top: Recognition of poly(U) by 12 and ds-polyAH+ by 13; bottom: Recognition of poly(dA)–poly(dT) by ...
Figure 6: The bis-phenanthridinium–adenine derivative 15 (LEFT) showed selectivity towards complementary UMP;...
Figure 7: The neomycin–methidium conjugate targeting DNA:RNA hybrid structures [80].
Figure 8: Two-colour RNA intercalating probe for cell imaging applications: Left: Chemical structure of EB-fl...
Figure 9: The ethidium bromide nucleosides 17 (top) and 18 (bottom). DNA duplex set 1 and 2 (E = phenanthridi...
Figure 10: Left: various DNA duplexes; DNA1 and DNA2 used to study the impact on the adjacent basepair type on...
Figure 11: Structure of 4,9-DAP derivative 19; Rright: MIAPaCa-2 cells stained with 10 μM 19 after 60 and 120 ...
Figure 12: Examples of naturally occurring phenanthridine analogues.
Preparation of phosphines through C–P bond formation
- Iris Wauters,
- Wouter Debrouwer and
- Christian V. Stevens
Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106
- catalysis (Table 16) [244]. Besides copper(I) iodide several other copper salts effectuated the reaction albeit in lower yields as did silver(I) iodide, palladium(II) chloride and platinum(II) chloride. Other transition metal catalysts such as gold(I) chloride, nickel(II) chloride and cobalt(II) chloride
Graphical Abstract
Scheme 1: Synthesis of P-stereogenic phosphines 5 using menthylphosphinite borane diastereomers 2.
Scheme 2: Enantioselective synthesis of chiral phosphines 10 with ephedrine as a chiral auxiliary.
Scheme 3: Chlorophosphine boranes 11a as P-chirogenic electrophilic building blocks.
Scheme 4: Monoalkylation of phenylphosphine borane 15 with methyl iodide in the presence of Cinchona alkaloid...
Scheme 5: Preparation of tetraphosphine borane 19.
Scheme 6: Using chiral chlorophosphine-boranes 11b as phosphide borane 20 precursors.
Scheme 7: Nickel-catalyzed cross-coupling (dppe = 1,2-bis(diphenylphosphino)ethane).
Scheme 8: Pd-catalyzed cross-coupling reaction with organophosphorus stannanes 30.
Scheme 9: Copper iodide catalyzed carbon–phosphorus bond formation.
Scheme 10: Thermodynamic kinetic resolution as the origin of enantioselectivity in metal-catalyzed asymmetric ...
Scheme 11: Ru-catalyzed asymmetric phosphination of benzyl and alkyl chlorides 35 with HPPhMe (36a, PHOX = pho...
Scheme 12: Pt-catalyzed asymmetric alkylation of secondary phosphines 36b.
Scheme 13: Different adducts 43 can result from hydrophosphination.
Scheme 14: Pt-catalyzed asymmetric hydrophosphination.
Scheme 15: Intramolecular hydrophosphination of phosphinoalkene 47.
Scheme 16: Organocatalytic asymmetric hydrophosphination of α,β-unsaturated aldehydes 59.
Scheme 17: Preparation of phosphines using zinc organometallics.
Scheme 18: Preparation of alkenylphosphines 71a from alkenylzirconocenes 69 (dtc = N,N-diethyldithiocarbamate,...
Scheme 19: SNAr with P-chiral alkylmethylphosphine boranes 13c.
Scheme 20: Synthesis of QuinoxP 74 (TMEDA = tetramethylethylenediamine).
Scheme 21: Pd-Mediated couplings of a vinyl triflate 76 with diphenylphosphine borane 13e.
Figure 1: Menthone (83) and camphor (84) derived chiral phosphines.
Scheme 22: Palladium-catalyzed cross-coupling reaction of vinyl tosylates 85 and 87 with diphenylphosphine bor...
Scheme 23: Attempt for the enantioselective palladium-catalyzed C–P cross-coupling reaction between an alkenyl...
Scheme 24: Enol phosphates 88 as vinylic coupling partners in the palladium-catalyzed C–P cross-coupling react...
Scheme 25: Nickel-catalyzed cross-coupling in the presence of zinc (dppe = 1,2-bis(diphenylphosphino)ethane).
Scheme 26: Copper-catalyzed coupling of secondary phosphines with vinyl halide 94.
Scheme 27: Palladium-catalyzed cross-coupling of aryl iodides 97 with organoheteroatom stannanes 30.
Scheme 28: Synthesis of optically active phosphine boranes 100 by cross-coupling with a chiral phosphine boran...
Scheme 29: Palladium-catalyzed P–C cross-coupling reactions between primary or secondary phosphines and functi...
Scheme 30: Enantioselective synthesis of a P-chirogenic phosphine 108.
Scheme 31: Enantioselective arylation of silylphosphine 110 ((R,R)-Et-FerroTANE = 1,1'-bis((2R,4R)-2,4-diethyl...
Scheme 32: Nickel-catalyzed arylation of diphenylphosphine 25d.
Scheme 33: Nickel-catalyzed synthesis of (R)-BINAP 116 (dppe = 1,2-bis(diphenylphosphino)ethane, DABCO = 1,4-d...
Scheme 34: Nickel-catalyzed cross-coupling between aryl bromides 119 and diphenylphosphine (25d) (dppp = 1,3-b...
Scheme 35: Stereocontrolled Pd(0)−Cu(I) cocatalyzed aromatic phosphorylation.
Scheme 36: Preparation of alkenylphosphines by hydrophosphination of alkynes.
Scheme 37: Palladium and nickel-catalyzed addition of P–H to alkynes 125a.
Scheme 38: Palladium-catalyzed asymmetric hydrophosphination of an alkyne 128.
Scheme 39: Ruthenium catalyzed hydrophosphination of propargyl alcohols 132 (cod = 1,5-cyclooctadiene).
Scheme 40: Cobalt-catalyzed hydrophosphination of alkynes 134a (acac = acetylacetone).
Scheme 41: Tandem phosphorus–carbon bond formation–oxyfunctionalization of substituted phenylacetylenes 125c (...
Scheme 42: Organolanthanide-catalyzed intramolecular hydrophosphination/cyclization of phosphinoalkynes 143.
Scheme 43: Hydrophosphination of alkynes 134c catalyzed by ytterbium-imine complexes 145 (hmpa = hexamethylpho...
Scheme 44: Calcium-mediated hydrophosphanylation of alkyne 134d.
Scheme 45: Formation and substitution of bromophosphine borane 151.
Scheme 46: General scheme for a nickel or copper catalyzed cross-coupling reaction.
Scheme 47: Copper-catalyzed synthesis of alkynylphosphines 156.
Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis
- Sebastian Krüger and
- Tanja Gaich
Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14
- 1,2-migration and subsequent formation of cis-divinylcyclopropane 269 yielding bridged bicycle 270. Chung and coworkers [210] discovered a related reaction pattern using platinum(II) as the catalyst. Depending on the attached rests on enyne 276 both possible cycloheptadienes (bridged 277 or annulated
Graphical Abstract
Scheme 1: Vogel’s first approach towards the divinylcyclopropane rearrangement [4] and characterization of cis-d...
Scheme 2: Transition states for the Cope rearrangement and the related DVCPR. Ts = transition state.
Scheme 3: Two possible mechanisms of trans-cis isomerizations of divinylcyclopropanes.
Scheme 4: Proposed biosynthesic pathway to ectocarpene (21), an inactive degradation product of a sexual pher...
Scheme 5: Proposed biosynthesis of occidenol (25) and related natural compounds.
Scheme 6: Gaich’s bioinspired system using the DVCPR to mimick the dimethylallyltryptophan synthase. DMAPP = ...
Scheme 7: Iguchi’s total synthesis of clavubicyclone, part 1.
Scheme 8: Iguchi’s total synthesis of clavubicyclone, part 2.
Scheme 9: Wender’s syntheses of the two pseudoguainanes confertin (50) and damsinic acid (51) and Pier’s appr...
Scheme 10: Overman’s total synthesis of scopadulcic acid B.
Scheme 11: Davies’ total syntheses of tremulenolide A and tremulenediol A.
Scheme 12: Davies formal [4 + 3] cycloaddition approach towards the formal synthesis of frondosin B.
Scheme 13: Davies and Sarpongs formal [4 + 3]-cycloaddition approach towards barekoxide (106) and barekol (107...
Scheme 14: Davies formal [4 + 3]-cycloaddition approach to 5-epi-vibsanin E (115) containing an intermediate c...
Scheme 15: Echavarren’s total synthesis of schisanwilsonene A (126) featuring an impressive gold-catalzed casc...
Scheme 16: Davies early example of a formal [4 + 3]-cycloaddition in alkaloids synthesis.
Scheme 17: Fukuyama’s total synthesis of gelsemine, part 1.
Scheme 18: Fukuyama’s total synthesis of gelsemine, featuring a divinylcyclopropane rearrangement, part 2.
Scheme 19: Kende’s total synthesis of isostemofoline, using a formal [4 + 3]-cycloaddition, including an inter...
Scheme 20: Danishefsky’s total synthesis of gelsemine, part 1.
Scheme 21: Danishefsky’s total synthesis of gelsemine, part 2.
Scheme 22: Fukuyama’s total synthesis of gelsemoxonine.
Scheme 23: Wender’s synthetic access to the core skeleton of tiglianes, daphnanes and ingenanes.
Scheme 24: Davies’ approach towards the core skeleton of CP-263,114 (212).
Scheme 25: Wood’s approach towards actinophyllic acid.
Scheme 26: Takeda’s approach towards the skeleton of the cyanthins, utilitizing the divinylcyclopropane rearra...
Scheme 27: Donaldson’s organoiron route towards the guianolide skeleton.
Scheme 28: Stoltz’s tandem Wolff/DVCPR rearrangement.
Scheme 29: Stephenson’s tandem photocatalysis/arylvinylcyclopropane rearrangement.
Scheme 30: Padwa’s rhodium cascade involving a DVCPR.
Scheme 31: Matsubara’s version of a DVCPR.
Scheme 32: Toste’s tandem gold-catalyzed Claisen-rearrangement/DVCPR.
Scheme 33: Ruthenium- and gold-catalyzed versions of tandem reactions involving a DVCPR.
Scheme 34: Tungsten, platinum and gold catalysed cycloisomerizations leading to a DVCPR.
Scheme 35: Reisman’s total synthesis of salvileucalin B, featuring an (undesired) vinylcyclopropyl carbaldehyd...
Scheme 36: Studies on the divinylepoxide rearrangement.
Scheme 37: Studies on the vinylcyclopropanecarbonyl rearrangement.
Scheme 38: Nitrogen-substituted variants of the divinylcyclopropane rearrangement.
True and masked three-coordinate T-shaped platinum(II) intermediates
- Manuel A. Ortuño,
- Salvador Conejero and
- Agustí Lledós
Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153
- . Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C–H bond-activation processes. Keywords: C–H bond activation; intermediate; platinum(II); reactive intermediates; three-coordinate; T-shaped; Review
Graphical Abstract
Figure 1: Qualitative orbital diagram for a d8 metal in ML4 square-planar and ML3 T-shaped complexes.
Figure 2: Walsh diagram for the d-block of a d8 ML3 complex upon bending of one L–M–L angle.
Figure 3: Neutral Y-shaped Pt complex Y1 [15]. Angles are given in degrees.
Figure 4: General classification of T-shaped Pt(II) structures according to the fourth coordination site.
Figure 5: Hydride, boryl and borylene true T-shaped Pt(II) complexes.
Figure 6: NHC-based true T-shaped Pt(II) complexes.
Figure 7: Phosphine-based agostic T-shaped Pt(II) complexes. Compounds in brackets correspond with hydrido–al...
Figure 8: Phenylpyridine and NHC-based agostic T-shaped Pt(II) complexes.
Figure 9: Counteranion coordination in T-shaped Pt(II) complexes.
Figure 10: Phosphine-based solvento Pt(II) complexes.
Figure 11: Nitrogen-based solvento Pt(II) complexes.
Figure 12: Pincer-based solvento Pt(II) complexes.
Figure 13: Structure of the QM/MM optimized cisplatin–protein adduct [94].
Figure 14: NMR coupling constants used for the characterization of three-coordinate Pt(II) species.
Figure 15: The chemical formula of the complexes discussed in Table 2.
Scheme 1: Halogen abstraction from 1.
Scheme 2: Halogen abstraction from 2 forming the dicationic complex T3 [22].
Scheme 3: Hydrogenation of complexes A5a and A5b [39].
Scheme 4: Hydrogenation of complexes 3 and A5c [40].
Scheme 5: Intermolecular C–H bond activation from T5a [28].
Scheme 6: Protonation of complexes 4 [35,36].
Scheme 7: Cyclometalation of 5 [43].
Scheme 8: Protonation of 6.
Scheme 9: Reductive elimination of ethane from 7.
Scheme 10: Reductive elimination of methane from six-coordinate Pt(IV) complexes.
Scheme 11: Proposed dissociative mechanism for the fluxional motion of dmphen in [Pt(Me)(dmphen)(PR3)]+ comple...
Figure 16: Feasible interactions for unsaturated intermediates 11b (left) and 12b (right) during fluxional mot...
Scheme 12: Halogen abstraction from 13a,b and subsequent cyclometalation to yield complexes A5a,b [39].
Scheme 13: Proposed mechanism for the acid-catalyzed cyclometalation of 14 via intermediate 15 [41].
Scheme 14: Proposed mechanism for the formation of 19 [102].
Scheme 15: Cyclometalation of 20 via thioether dissociation [117].
Figure 17: Gibbs energy profile (in chloroform solvent) for the cyclometalation of 23 [120].
Scheme 16: Coordination of tmtu to 29 and subsequent C–H bond activation via three-coordinate species 31 and 32...
Scheme 17: Cyclometalation process of NHC-based Pt(II) complexes [28,44].
Scheme 18: Cyclometalation process of complex A9 [43].
Scheme 19: “Rollover” reaction of 38 and subsequent oligomerization [123].
Scheme 20: Proposed mechanism for the formation of cyclometalated species 44 [124].
Scheme 21: Self-assembling process of 45 by “rollover” reaction [126].
Scheme 22: “Rollover” reaction of A9. Energies (solvent) in kcal mol−1 [127].
Scheme 23: Proposed mechanisms for the “rollover” cyclometalation of 52 in gas-phase ion-molecule reactions [128].
Scheme 24: β-H elimination and 1,2-insertion equilibrium involving A1d and the subsequent generation of 57 [35].
Scheme 25: Proposed mechanism for thermolysis of 7b and 7c in benzene-d6 and cyclohexane-d12 solvents [101].
Scheme 26: β-H elimination process of A11a [28].
Scheme 27: Intermolecular C–H bond activation from 62 [95].
Scheme 28: Reductive elimination of methane from 65 followed by CD3CN coordination or C–D bond-activation proc...
Figure 18: DFT-optimized structures describing the κ2 (69, left) and κ3 (69’, right) coordination modes of [Pt...
Scheme 29: Intermolecular arene C–H bond activation from NHC-based complexes [28].
Figure 19: Energy profiles (in benzene solvent) for the benzene C–H bond activation from A11a, A11b, T5a and T...
Scheme 30: Intermolecular arene C–H bond activation from PNP-based complex 71 [12].
Scheme 31: Intermolecular C–H bond-activation by gas-phase ion-molecule reactions of 74 [7,142].
Scheme 32: Dihydrogen activation through complexes A5a, A5b [39], A5c [40] and S1a [54].
Scheme 33: Dihydrogen activation through complexes A7 and 16 [41]. For a: see Scheme 13.
Scheme 34: Br2 and I2 bond activations through complexes A11a and T5a [143].
Scheme 35: Detection and isolation of the Pt(III) complex 81a [143].
Scheme 36: Cl2 bond activation through complexes 82 and 83 [144].
Scheme 37: cis–trans Isomerization mechanism of the solvento Pt(II) complexes S5 [2,61].
Figure 20: Energy profiles for the isomerization of complexes [Pt(R)(PMe3)2(NCMe)]+ where R means Me (85a, red...
Figure 21: DFT-optimized structure of intermediate 86 [62]. Bond distances in angstrom and angles in degrees.
Scheme 38: Proposed dissociative ligand-substitution mechanism of cis-[Pt(R)2S2] complexes (87) [117].
Scheme 39: Proposed mechanisms for the ligand substitution of the dinuclear species 91 [146].
Synthesis of a novel chemotype via sequential metal-catalyzed cycloisomerizations
- Bo Leng,
- Stephanie Chichetti,
- Shun Su,
- Aaron B. Beeler and
- John A. Porco Jr.
Beilstein J. Org. Chem. 2012, 8, 1338–1343, doi:10.3762/bjoc.8.153
- reaction mixture was added tetrakis(acetonitrile)copper(I) hexafluorophosphate (1.7 mg, 0.005 mmol), and the reaction mixture was stirred at room temperature for 1 h. Platinum(II) chloride (1.2 mg, 0.005 mmol) was added and the reaction mixture was heated to 80 °C for 5 h. The reaction mixture was
Graphical Abstract
Scheme 1: Cycloisomerization/nucleophilic addition of alkynyl benzaldehyde 1 to isochromene 2.
Figure 1: Reaction screen with diynyl benzaldehyde 3.
Scheme 2: Sequential cycloisomerizations of substrate 3. Condition A: PtCl2 (10 mol %), Cu(MeCN)4PF6 (10 mol ...
Figure 2: X-ray crystal structure of cyclopropane 6.
Scheme 3: Proposed reaction pathway for diastereoselective, sequential cycloisomerization.
Scheme 4: Proposed alternative reaction pathway affording 23.
Recent developments in gold-catalyzed cycloaddition reactions
- Fernando López and
- José L. Mascareñas
Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124
- and reductive eliminations). Therefore, platinum(II) and particularly gold(I) or (III) complexes tend to activate alkynes, alkenes or allenes in a highly chemoselective manner; activation that opens interesting reaction pathways that usually involve carbocationic intermediates. Also very important is
- group of L. Zhang also developed several annulation reactions of allenyl esters generated in situ by a metal-catalyzed 1,3-migration of propargyl precursors [85][86]. In particular, they showed that propargyl indole-3-acetates 41 undergo gold(I)- or platinum(II)-catalyzed 1,3-migration to acyloxy
- to those previously proposed by Gagosz, evolves through a cyclopropane fragmentation and protodeauration to afford the products 48 in good yields and excellent stereoselectivities. Based on these and other reports demonstrating the ability of gold(I) and platinum(II) catalysts to induce reactions of
Graphical Abstract
Scheme 1: AuCl3-catalyzed benzannulations reported by Yamamoto.
Scheme 2: Synthesis of 9-oxabicyclo[3.3.1]nona-4,7-dienes from 1-oxo-4-oxy-5-ynes [40].
Scheme 3: Stereocontrolled oxacyclization/(4 + 2)-cycloaddition cascade of ketone–allene substrates [43].
Scheme 4: Gold-catalyzed synthesis of polycyclic, fully substituted furans from 1-(1-alkynyl)cyclopropyl keto...
Scheme 5: Gold-catalyzed 1,3-dipolar cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with nitrones [47].
Scheme 6: Enantioselective 1,3-dipolar cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with nitrones [48].
Scheme 7: Gold-catalyzed 1,3-dipolar cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with α,β-unsaturated imine...
Scheme 8: Gold-catalyzed (4 + 3) cycloadditions of 1-(1-alkynyl)oxiranyl ketones [50].
Scheme 9: (3 + 2) Cycloaddition of gold-containing azomethine ylides [52].
Scheme 10: Gold-catalyzed generation and reaction of azomethine ylides [53].
Scheme 11: Gold-catalyzed intramolecular (4 + 2) cycloadditions of unactivated alkynes and dienes [55].
Scheme 12: Gold-catalyzed preparation of bicyclo[4.3.0]nonane derivatives from dienol silyl ethers [59].
Scheme 13: Gold(I)-catalyzed intramolecular (4 + 2) cycloadditions of arylalkynes or 1,3-enynes with alkenes [60].
Scheme 14: Gold(I)-catalyzed intermolecular (2 + 2) cycloaddition of alkynes with alkenes [62].
Scheme 15: Metal-catalyzed cycloaddition of alkynes tethered to cycloheptatriene [65].
Scheme 16: Gold-catalyzed cycloaddition of functionalized ketoenynes: Synthesis of (+)-orientalol F [68].
Scheme 17: Gold-catalyzed intermolecular cyclopropanation of enynes with alkenes [70].
Scheme 18: Gold-catalyzed intermolecular hetero-dehydro Diels–Alder cycloaddition [72].
Figure 1: Gold-catalyzed 1,2- or 1,3-acyloxy migrations of propargyl esters.
Scheme 19: Gold(I)-catalyzed stereoselective olefin cyclopropanation [74].
Scheme 20: Reaction of propargylic benzoates with α,β-unsaturated imines to give azepine cycloadducts [77].
Scheme 21: Gold-catalyzed (3 + 3) annulation of azomethine imines with propargyl esters [81].
Scheme 22: Gold(I)-catalyzed isomerization of 5-en-2-yn-1-yl acetates [83].
Scheme 23: (3 + 2) and (2 + 2) cycloadditions of indole-3-acetates 41 [85,86].
Scheme 24: Gold(I)-catalyzed (2 + 2) cycloaddition of allenenes [87].
Scheme 25: Formal (3 + 2) cycloaddition of allenyl MOM ethers and alkenes [90].
Scheme 26: (4 + 3) Cycloadditions of allenedienes [97,98].
Scheme 27: Gold-catalyzed transannular (4 + 3) cycloaddition reactions [101].
Scheme 28: Gold(I)-catalyzed (4 + 2) cycloadditions of allenedienes [102].
Scheme 29: Enantioselective gold(I)-catalyzed (4 + 2) cycloadditions of allenedienes [88,102,104].
Scheme 30: (3 + 2) versus (2 + 2) Cycloadditions of allenenes [87,99].
Figure 2: NHC ligands with different π-acceptor properties [106].
Scheme 31: (3 + 2) versus (2 + 2) Cycloadditions of allenenes [106].
Scheme 32: Gold(I)-catalyzed intermolecular (4 + 2) cycloaddition of allenamides and acyclic dienes [109].
High chemoselectivity in the phenol synthesis
- Matthias Rudolph,
- Melissa Q. McCreery,
- Wolfgang Frey and
- A. Stephen K. Hashmi
Beilstein J. Org. Chem. 2011, 7, 794–801, doi:10.3762/bjoc.7.90
- dinuclear gold(I) complex 36 [44] gave the same result (Figure 3). When the catalyst was changed to platinum(II) chloride in acetone, a complex mixture of inseparable products was obtained. Since the two diastereoisomers 28a and 28b with the propargylic stereocenters were separable, we investigated the gold
Graphical Abstract
Scheme 1: Mechanism of the furan–yne reaction.
Scheme 2: Efforts for intermolecular trapping with olefins failed.
Scheme 3: Efforts for intermolecular trapping with ketones failed.
Scheme 4: Potential products of an intramolecular trapping experiment with substrate 8.
Scheme 5: Synthesis of the substrate 8.
Scheme 6: With substrate 8 the product of the phenol synthesis was exclusively obtained.
Figure 1: Solid-state molecular structure of 10.
Scheme 7: Potential products of an intramolecular trapping experiment with substrate 16.
Scheme 8: Synthesis of the substrate 16.
Figure 2: Solid-state molecular structure of 28a.
Scheme 9: With substrate 16 the product of the phenol synthesis is obtained exclusively.
Figure 3: Catalysts 34, 35 and 36.
Figure 4: 1H NMR spectra of the separated diastereoisomers of the substrates for catalysis 28 (left) and of t...
Figure 5: Structure of the desilylation product 38.
Scheme 10: Potential products of an intramolecular trapping experiment with substrate 39.
Scheme 11: Synthesis of the substrate 39.
Scheme 12: With substrate 39 and 45 exclusively the product of the phenol synthesis is obtained.
Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers
- Daniel Crespy and
- Katharina Landfester
Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130
- copolymerized with styrene to yield functionalized particles [34][35] and their uptake by cells was studied [34]. In general, with increased functional groups, an increase in the uptake into cells could be observed. Copolymer particles of styrene and acrylic acid were used to encapsulate a platinum(II) complex
Graphical Abstract
Figure 1: Copolymerization of 2 monomers A and B with different polarities in direct miniemlusions with the d...
Figure 2: Interfacial alternating radical copolymerization between dibutyl maleate and vinyl gluconamide for ...
Figure 3: Chemical structures of the surfmers for radical polymerization in miniemulsions: a: sodium vinylben...
Scheme 1: Synthesis of the macroinitiator for ROMP in direct miniemulsion [71].
Figure 4: Monomers used in ionic miniemulsion polymerization. a: octamethylcyclotetrasiloxane [9,74], b: 1,3,5-tris...
Figure 5: Enzymatic reactions in miniemulsion droplets (reproduced with permission from [91]. Copyright (2003) Wi...
Figure 6: Chemical structure of a: polyaniline (leucoemeraldine), b: polypyrrole, c: poly(ethylene dioxythiop...
Figure 7: Transmission electron micrograph of polyurethane capsules synthesized by interfacial polyaddition i...
Figure 8: Schematics for the polycondensation reaction between hydrophobic alcohols and carboxylic acids surr...
Scheme 2: Polyimide from the reaction performed in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoro...
Figure 9: a: TEM micrograph of the cubic structures, b: proposed mechanism for the production of the nanocube...
