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Search for "X-ray structural analysis" in Full Text gives 32 result(s) in Beilstein Journal of Organic Chemistry.
The chemistry of bisallenes
- Henning Hopf and
- Georgios Markopoulos
Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225
Graphical Abstract
Figure 1: Loschmidt’s structure proposal for benzene (1) (Scheme 181 from [3]) and the corresponding modern stru...
Figure 2: The first isolated bisallenes.
Figure 3: Carbon skeletons of selected bisallenes discussed in this review.
Scheme 1: The preparation of 1,2,4,5-hexatetraene (2).
Scheme 2: The preparation of a conjugated bisallene by the DMS-protocol.
Scheme 3: Preparation of the 3-deuterio- and 3,4-dideuterio derivatives of 24.
Scheme 4: A versatile method to prepare alkylated conjugated bisallenes and other allenes.
Scheme 5: A preparation of 3,4-dimethyl-1,2,4,5-hexatetraene (38).
Scheme 6: A (C6 + 0)-approach to 1,2,4,5-hexatetraene (2).
Scheme 7: The preparation of a fully alkylated bisallenes from a 2,4-hexadiyne-1,6-diol diacetate.
Scheme 8: The preparation of the first phenyl-substituted conjugated bisallenes 3 and 4.
Scheme 9: Selective hydrogenation of [5]cumulenes to conjugated bisallenes: another (C6 + 0)-route.
Scheme 10: Aryl-substituted conjugated bisallenes by a (C3 + C3)-approach.
Scheme 11: Hexaphenyl-1,2,4,5-hexatetraene (59) by a (C3 + C3)-approach.
Scheme 12: An allenation route to conjugated bisallenes.
Scheme 13: The preparation of 3,4-difunctionalized conjugated bisallenes.
Scheme 14: Problems during the preparation of sulfur-substituted conjugated bisallenes.
Scheme 15: The preparation of 3,4-dibromo bisallenes.
Scheme 16: Generation of allenolates by an oxy-Cope rearrangement.
Scheme 17: A linear trimerization of alkynes to conjugated bisallenes: a (C2 + C2 + C2)-protocol.
Scheme 18: Preparation of a TMS-substituted conjugated bisallene by a C3-dimerization route.
Scheme 19: A bis(trimethylsilyl)bisallene by a C3-coupling protocol.
Scheme 20: The rearrangement of highly substituted benzene derivatives into their conjugated bisallenic isomer...
Scheme 21: From fully substituted benzene derivatives to fully substituted bisallenes.
Scheme 22: From a bicyclopropenyl to a conjugated bisallene derivative.
Scheme 23: The conversion of a bismethylenecyclobutene into a conjugated bisallene.
Scheme 24: The preparation of monofunctionalized bisallenes.
Scheme 25: Preparation of bisallene diols and their cyclization to dihydrofurans.
Scheme 26: A 3,4-difunctionalized conjugated bisallene by a C3-coupling process.
Scheme 27: Preparation of a bisallenic diketone by a coupling reaction.
Scheme 28: Sulfur and selenium-substituted bisallenes by a [2.3]sigmatropic rearrangement.
Scheme 29: The biallenylation of azetidinones.
Scheme 30: The preparation of a fully ferrocenylated conjugated bisallene.
Scheme 31: The first isomerization of a 1,5-hexadiyne to a 1,2,4,5-hexatetraene.
Scheme 32: The preparation of alkynyl-substituted bisallenes by a C3-dimerization protocol.
Scheme 33: Preparation of another completely ferrocenylated bisallene.
Scheme 34: The cyclization of 1,5-hexadiyne (129) to 3,4-bismethylenecyclobutene (130) via 1,2,4,5-hexatetraen...
Scheme 35: Stereochemistry of the thermal cyclization of bisallenes to bismethylenecyclobutenes.
Scheme 36: Bisallene→bismethylenecyclobutene ring closures in the solid state.
Scheme 37: A bisallene cyclization/dimerization reaction.
Scheme 38: A selection of Diels–Alder additions of 1,2,4,5-hexatetraene with various double-bond dienophiles.
Scheme 39: The stereochemistry of the [2 + 4] cycloaddition to conjugated bisallenes.
Scheme 40: Preparation of azetidinone derivatives from conjugated bisallenes.
Scheme 41: Cycloaddition of heterodienophiles to a conjugated bisallene.
Scheme 42: Addition of triple-bond dienophiles to conjugated bisallenes.
Scheme 43: Sulfur dioxide addition to conjugated bisallenes.
Scheme 44: The addition of a germylene to a conjugated bisallene.
Scheme 45: Trapping of conjugated bisallenes with phosphinidenes.
Scheme 46: The cyclopropanantion of 1,2,4,5-hexatetraene (2).
Scheme 47: Photochemical reactions involving conjugated bisallenes.
Scheme 48: Base-catalyzed isomerizations of conjugated bisallenes.
Scheme 49: Ionic additions to a conjugated bisallene.
Scheme 50: Oxidation reactions of a conjugated bisallene.
Scheme 51: The mechanism of oxidation of the bisallene 24.
Scheme 52: CuCl-catalyzed cyclization of 1,2,4,5-hexatetraene (2).
Scheme 53: The conversion of conjugated bisallenes into cyclopentenones.
Scheme 54: Oligomerization of a conjugated bisallene by nickel catalysts.
Scheme 55: Generation of 1,2,5,6-heptatetraene (229) as a reaction intermediate.
Scheme 56: The preparation of a stable derivative of 1,2,5,6-heptatetraene.
Scheme 57: A bisallene with a carbonyl group as a spacer element.
Scheme 58: The first preparation of 1,2,6,7-octatetraene (242).
Scheme 59: Preparation of 1,2,6,7-octatetraenes by (C4 + C4)-coupling of enynes.
Scheme 60: Preparation of 1,2,6,7-octatetraenes by (C4 + C4)-coupling of homoallenyl bromides.
Scheme 61: Preparation of 1,2,6,7-octatetraenes by alkylation of propargylic substrates.
Scheme 62: Preparation of two highly functionalized 1,2,6,7-octatetraenes.
Scheme 63: Preparation of several higher α,ω-bisallenes.
Scheme 64: Preparation of different alkyl derivatives of α,ω-bisallenes.
Scheme 65: The preparation of functionalized 1,2,7,8-nonatetraene derivatives.
Scheme 66: Preparation of functionalized α,ω-bisallenes.
Scheme 67: The preparation of an α,ω-bisallene by direct homologation of an α,ω-bisalkyne.
Scheme 68: The gas-phase pyrolysis of 4,4-dimethyl-1,2,5,6-heptatetraene (237).
Scheme 69: Gas-phase pyrolysis of 1,2,6,7-octatetraene (242).
Scheme 70: The cyclopropanation of 1,2,6,7-octatetraene (242).
Scheme 71: Intramolecular cyclization of 1,2,6,7-octatetraene derivatives.
Scheme 72: The gas-phase pyrolysis of 1,2,7,8-nonatetraene (265) and 1,2,8,9-decatetraene (266).
Scheme 73: Rh-catalyzed cyclization of a functionalized 1,2,7,8-nonatetraene.
Scheme 74: A triple cyclization involving two different allenic substrates.
Scheme 75: Bicyclization of keto derivatives of 1,2,7,8-nonatetraene.
Scheme 76: The preparation of complex organic compounds from functionalized bisallenes.
Scheme 77: Cycloisomerization of an α,ω-bisallene containing a C9 tether.
Scheme 78: Organoborane polymers from α,ω-bisallenes.
Scheme 79: Preparation of trans- (337) and cis-1,2,4,6,7-octapentaene (341).
Scheme 80: The preparation of 4-methylene-1,2,5,6-heptatetraene (349).
Scheme 81: The preparation of acetylenic bisallenes.
Scheme 82: The preparation of derivatives of hydrocarbon 351.
Scheme 83: The construction of macrocyclic alleno-acetylenes.
Scheme 84: Preparation and reactions of 4,5-bismethylene-1,2,6,7-octatetraene (365).
Scheme 85: Preparation of 1,2-bis(propadienyl)benzene (370).
Scheme 86: The preparation of 1,4-bis(propadienyl)benzene (376).
Scheme 87: The preparation of aromatic and heteroaromatic bisallenes by metal-mediated coupling reactions.
Scheme 88: Double cyclization of an aromatic bisallene.
Scheme 89: Preparation of an allenic [15]paracyclophane by a ring-closing metathesis reaction of an aromatic α...
Scheme 90: Preparation of a macrocyclic ring system containing 1,4-bis(propadienyl)benzene units.
Scheme 91: Preparation of copolymers from 1,4-bis(propadienyl)benzene (376).
Scheme 92: A boration/copolymerization sequence of an aromatic bisallene and an aromatic bisacetylene.
Scheme 93: Formation of a layered aromatic bisallene.
Figure 4: The first members of the semicyclic bisallene series.
Scheme 94: Preparation of the first bis(vinylidene)cyclobutane derivative.
Scheme 95: Dimerization of strain-activated cumulenes to bis(vinylidene)cyclobutanes.
Scheme 96: Photodimerization of two fully substituted butatrienes in the solid state.
Scheme 97: Preparation of the two parent bis(vinylidene)cyclobutanes.
Scheme 98: The preparation of 1,3-bis(vinylidene)cyclopentane and its thermal isomerization.
Scheme 99: The preparation of the isomeric bis(vinylidene)cyclohexanes.
Scheme 100: Bi- and tricyclic conjugated bisallenes.
Scheme 101: A selection of polycyclic bisallenes.
Scheme 102: The first endocyclic bisallenes.
Figure 5: The stereochemistry of 1,2,6,7-cyclodecatetraene.
Scheme 103: The preparation of several endocyclic bisallenes.
Scheme 104: Synthesis of diastereomeric derivatives of 1,2,6,7-cyclodecatetraene.
Scheme 105: Preparation of a derivative of 1,2,8,9-cyclotetradecatetraene.
Scheme 106: The preparation of keto derivatives of cyclic bisallenes.
Scheme 107: The preparation of cyclic biscumulenic ring systems.
Scheme 108: Cyclic bisallenes in natural- and non-natural-product chemistry.
Scheme 109: The preparation of iron carbonyl complexes from cyclic bisallenes.
Figure 6: A selection of unknown exocyclic bisallenes that should have interesting chemical properties.
Scheme 110: The thermal isomerization of 1,2-diethynylcyclopropanes and -cyclobutanes.
Scheme 111: Intermediate generation of a cyclooctapentaene.
Scheme 112: Attempted preparation of a cyclodecahexaene.
Scheme 113: The thermal isomerization of 1,5,9-cyclododecatriyne (511) into [6]radialene (514).
Scheme 114: An isomerization involving a diketone derived from a conjugated bisallene.
Scheme 115: Typical reaction modes of heteroorganic bisallenes.
Scheme 116: Generation and thermal behavior of acyclic hetero-organic bisallenes.
Scheme 117: Generation of bis(propadienyl)thioether.
Scheme 118: The preparation of a bisallenic sulfone and its thermal isomerization.
Scheme 119: Bromination of the bisallenic sulfone 535.
Scheme 120: Metalation/hydrolysis of the bisallenic sulfone 535.
Scheme 121: Aromatic compounds from hetero bisallenes.
Scheme 122: Isomerization/cyclization of bispropargylic ethers.
Scheme 123: The preparation of novel aromatic systems by base-catalyzed isomerization of bispropargyl ethers.
Scheme 124: The isomerization of bisacetylenic thioethers to bicyclic thiophenes.
Scheme 125: Aromatization of macrocyclic bispropargylic sulfides.
Scheme 126: Preparation of ansa-compounds from macrocyclic bispropargyl thioethers.
Scheme 127: Alternate route for cyclization of a heterorganic bisallene.
Scheme 128: Multiple isomerization/cyclization of “double” bispropargylic thioethers.
Scheme 129: Preparation of a bisallenyl disulfide and its subsequent bicyclization.
Scheme 130: Thermal cyclization of a bisallenyl thiosulfonate.
Scheme 131: Some reactions of heteroorganic bisallenes with two sulfur atoms.
Scheme 132: Further methods for the preparation of heteroorganic bisallenes.
Scheme 133: Cyclization reactions of heteroorganic bisallenes.
Scheme 134: Thermal cycloadditions of bisallenic tertiary amines.
Scheme 135: Cyclization of a bisallenic tertiary amine in the presence of a transition-metal catalyst.
Scheme 136: A Pauson–Khand reaction of a bisallenic ether.
Scheme 137: Formation of a 2:1adduct from two allenic substrates.
Scheme 138: A ring-forming silastannylation of a bisallenic tertiary amine.
Scheme 139: A three-component cyclization involving a heterorganic bisallene.
Scheme 140: Atom-economic construction of a complex organic framework from a heterorganic α,ω-bisallene.
The preferred conformation of erythro- and threo-1,2-difluorocyclododecanes
- Yi Wang,
- Peer Kirsch,
- Tomas Lebl,
- Alexandra M. Z. Slawin and
- David O'Hagan
Beilstein J. Org. Chem. 2012, 8, 1271–1278, doi:10.3762/bjoc.8.143
- by using a combination of 19F{1H} NMR spectroscopy, computational studies and, in the case of the threo isomer, X-ray structural analysis. In the lowest energy conformers for both diastereoisomers the vicinal C–F bonds are located corner/edge, rather than edge/edge. These structures avoid placing a C
Graphical Abstract
Figure 1: The Dunitz and Shearer structure of cyclododecane (1) [1,2]. There are four endo hydrogens above and fou...
Figure 2: Crystal structures of (a) 1,1,4,4- (b) 1,1,7,7- and (c) 1,1,6,6-tetrafluorocyclododecanes (2–4) , i...
Figure 3: Erythro- and threo-1,2-difluorocyclododecanes (5a and 5b).
Scheme 1: Synthetic routes to erythro- (5a) and threo-1,2-difluorocyclododecane (5b).
Figure 4: X-ray crystal structure of threo-1,2-difluorocyclododecane (5b) showing corner angles and represent...
Figure 5: Variable-temperature 19F{1H} NMR of erythro- (5a) and threo-1,2-difluorocyclododecane (5b).
Figure 6: Calculated relative energies of the conformations of the erythro (5a) and threo (5b) stereoisomers ...
Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes
- Henning Hopf,
- Vitaly Raev and
- Peter G. Jones
Beilstein J. Org. Chem. 2011, 7, 658–667, doi:10.3762/bjoc.7.78
- : paracyclophanes; photoadditions; photoisomerizations; proximity effects; topochemical reaction control; vinylcyclopropanes; X-ray structural analysis; Introduction Photodimerizations of crystalline aromatic or olefinic compounds are among the oldest known organic photoreactions. In this type of reaction the
- -conformation, which has been shown to be present as a conformer in the solid state by X-ray structural analysis does not photocyclize to 8. Moreover, syn,syn-7 is evidently too sterically hindered (by repulsion of the relevant hydrogen atoms as shown in Scheme 3) to be part of the conformational equilibrium
Graphical Abstract
Scheme 1: [2.2]Paracyclophanes as scaffolds for intraannular photodimerization reactions in solution.
Scheme 2: Stereospecific intramolecular [2+2]photoadditions using [2.2]paracyclophane spacers.
Scheme 3: Different conformations of pseudo-geminal divinyl[2.2]paracyclophane.
Scheme 4: Preparation of tetraene 11.
Scheme 5: Photolysis of tetraene 11.
Figure 1: The molecule of compound 13 in the crystal. Ellipsoids correspond to 30% probability levels.
Scheme 6: Photolysis of trans,trans-dienal 10.
Figure 2: The molecule of compound 15 in the crystal. Ellipsoids correspond to 30% probability levels.
Scheme 7: Cis–trans-isomerizations of the double bonds of the pseudo-geminal cyclophanes 11 and 19.
Scheme 8: Preparation of the vinylcyclopropanes 22–24.
Figure 3: The two independent molecules of compound Z,Z-22 in the crystal. Ellipsoids correspond to 50% proba...
Figure 4: The molecule of compound 23 in the crystal. Ellipsoids correspond to 50% probability levels.
Figure 5: The molecule of compound 24 in the crystal. Ellipsoids correspond to 30% probability levels.
An efficient and practical entry to 2-amido-dienes and 3-amido-trienes from allenamides through stereoselective 1,3-hydrogen shifts
- Ryuji Hayashi,
- John B. Feltenberger,
- Andrew G. Lohse,
- Mary C. Walton and
- Richard P. Hsung
Beilstein J. Org. Chem. 2011, 7, 410–420, doi:10.3762/bjoc.7.53
- . Supporting Information File 140: X-Ray structural analysis and information for compound 10b. Acknowledgements Authors thank NIH (GM066055) for financial support and Dr. Victor Young (University of Minnesota) for X-ray structural analysis.
Graphical Abstract
Scheme 1: 1,3-Hydrogen shifts of allenes.
Scheme 2: Synthesizing amido-dienes from allenamides.
Scheme 3: Synthesis of 1-amido-dienes from allenamides.
Figure 1: X-ray Structure of 10b.
Figure 2: Proposed mechanistic models.
Scheme 4: A favored pro-E TS.
Scheme 5: Unexpected competing 1,7-hydrogen shifts.
Scheme 6: Applications in pericyclic ring-closure.
Scheme 7: Cyclic 2-amido-diene synthesis.
Novel loop-like aromatic compounds: a further step on the road to nanobelts and nanotubes
- Venkataramana Rajuri,
- Dariush Ajami,
- Gaston R. Schaller,
- Christian Näther and
- Rainer Herges
Beilstein J. Org. Chem. 2010, 6, No. 30, doi:10.3762/bjoc.6.30
- , hexafluorophosphate and hexafluoroantimonate, silver hexafluoroantimonate gave crystals with 2 on applying the diffusion method with dichloromethane/diethylether (Scheme 2). However, crystals of the corresponding silver complex with 3, suitable for X-ray structural analysis, could not be obtained. A number of
Graphical Abstract
Scheme 1: Synthesis of 1 and 3. (a) Pyridazine, toluene, reflux, 20 h; (b) NaI, DMF, 65 °C, 15 h.
Scheme 2: Synthesis of 2 and 4. (a) NaI, DMF, 65 °C, 24 h; (b) AgSbF6, THF.
Figure 1: ORTEP drawing of the crystal structures: a) 2 and b) 3. For additional perspective representations ...
Figure 2: a) ORTEP drawing of the crystal structure of 4. Ag+ and Ag+, describe the two disordered positions ...
Scheme 3: Synthesis of 5 and 6. (a) Toluene, 90 °C, 15 h.
Figure 3: ORTEP drawing of the crystal structures: a) 5b and b) 6. For additional perspective representations...
The efficient synthesis of dibenzo[d,d′]benzo[1,2-b:4,3-b′]dithiophene and cyclopenta[1,2-b:4,3-b′]bis(benzo[d]thiophen)-6-one
- Zhihua Wang,
- Sheng Zhu,
- Jianwu Shi and
- Hua Wang
Beilstein J. Org. Chem. 2009, 5, No. 55, doi:10.3762/bjoc.5.55
- of 1 from 3 is about 60%. When dilithiated 3 was treated with N,N-dimethylcarbamoyl chloride (DMC) at low temperature (−50 °C), a new helical ketone, cyclopenta[1,2-b:4,3-b′]bis(benzo[d]thiophen)-6-one (2), was obtained in 79% yield. X-ray structural analysis A single crystal of 1 was obtained by the
Graphical Abstract
Figure 1: Chemical structures of 1 and 2.
Scheme 1: Synthetic route to 1 and 2. Reagents and conditions: (a) (i) n-BuLi (2.3 equiv), Et2O, reflux; (ii)...
Figure 2: Molecular structure and conformation of 1.
Figure 3: Crystal packing structure of 1.
Figure 4: UV–vis spectra of 1 and 2 in chloroform ([C] = 1 × 10−5 M).
A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions
- Marc Debeaux,
- Kai Brandhorst,
- Peter G. Jones,
- Henning Hopf,
- Jörg Grunenberg,
- Wolfgang Kowalsky and
- Hans-Hermann Johannes
Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31
- the reaction products is proposed and supported by DFT calculations. Keywords: consecutive reactions; intramolecular cyclization; molecular modelling; spiro compounds; X-ray structural analysis; Introduction Compounds for optoelectronic applications with electroluminescent (e.g. organic light
Graphical Abstract
Scheme 1: Behaviour of benzanthrone (1) towards phenylmagnesium chloride (a), phenyl lithium (b), and bipheny...
Figure 1: 1H NMR spectra (200 MHz) of 4 in CDCl3 solution and time dependence.
Scheme 2: Proposed mechanism for the formation of 4 and its oxidation to 7.
Scheme 3: Conversion of the enol 4 under acidic conditions and reaction products.
Scheme 4: Proposed mechanism for the formation of spiro compound 11 and bicyclo[4.3.1]decane derivative 12.
Scheme 5: Proposed mechanism for the formation of 13.
Scheme 6: Proposed mechanism for the formation of 18 as a hydride source and further conversion to 7.
Figure 2: Ellipsoid representation (50% level) of compound 7 in the crystal.
Figure 3: Packing diagram of compound 7 viewed parallel to b; hydrogen bonds C-H···O are indicated by dashed ...
Figure 4: Ellipsoid representation (50% level) of compound 11 in the crystal.
Figure 5: Packing diagram of compound 11 viewed perpendicular to the bc plane; hydrogen bonds C-H···π are ind...
Figure 6: Ellipsoid representation (50% level) of compound 13 (d6-DMSO solvate) in the crystal. Hydrogen bond...
Figure 7: Packing diagram of compound 13 viewed parallel to c; DMSO molecules (including their hydrogen bonds...
