Modulating NHC catalysis with fluorine

• Yannick P. Rey and
• Ryan Gilmour

Beilstein J. Org. Chem. 2013, 9, 2812–2820, doi:10.3762/bjoc.9.316

• catalyst 10 (Scheme 3; lower) was prepared in a short synthesis starting from the primary bromide 23 [22]. Hydrogenolysis (24, 67%) [41] and subsequent conversion to the triazolium salt completed the short synthesis (52% over 3 steps). X-Ray structural analysis of 5, 6 and 7 The X-ray crystal structures of

The preparation of several 1,2,3,4,5-functionalized cyclopentane derivatives

• André S. Kelch,
• Peter G. Jones,
• Ina Dix and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 1705–1712, doi:10.3762/bjoc.9.195

• with various bromination reagents. Whenever possible we confirm the structures of intermediate compounds or byproducts by X-ray structural analysis. Results and Discussion cis,cis,cis,cis-1,2,3,4,5-Pentakis(hydroxymethyl)cyclopentane (16) and derivatives The pentaalcohol 16 is a known compound, having

• silica gel, the main isomer began to crystallize partially from the highly viscous hydrogenation mixture after standing for several months. The crystals obtained were suitable for X-ray structural analysis, which showed that this isomer has the cis,cis,cis,trans-geometry, i.e. 26 (Figure 3). The

• the best results. Under these conditions the hexabromide 32 was produced in 45% yield. The structure of this cyclopentadiene derivative was derived from its spectroscopic data (see Supporting Information File 1) and also by an X-ray structural analysis (Figure 4). A rationalization of the route from 8

Isolation and X-ray characterization of palladium–N complexes in the guanylation of aromatic amines. Mechanistic implications

• Abdessamad Grirrane,
• Hermenegildo Garcia and
• Eleuterio Álvarez

Beilstein J. Org. Chem. 2013, 9, 1455–1462, doi:10.3762/bjoc.9.165

• complexes of the type of bis(guanidino)Pd(II) (4a–c) (Scheme 2) whose structures have been characterized by single-crystal X-ray structural analysis, as well as to obtain evidence for the intermediacy of these complexes in the catalytic process. Overall the present data reinforce the previous proposal for

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

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

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

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.

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

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

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