- Efficient Synthesis of Bis(dibromomethyl)arenes as Important Precursors of Synthetically Useful Dialdehydes
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This work presents an efficient synthesis of bis(dibromomethyl)benzenes and a bis(dibromomethyl)thiophene as precursors of aromatic dialdehydes by bromination of dimethyl-substituted arenes under various reaction conditions (yields up to 99%). Several new variants of this reaction, including the use of N-bromosuccinimide (NBS) and bromine, and various solvents to replace carbon tetrachloride, benzene and carbon disulfide, were also tested. In the optimised protocols, the inconvenient solvents were replaced by 1,2-dichloroethane (DCE) and/or acetonitrile. In the DCE protocols, we reduced reaction times 24-32-fold, reduced the amount of NBS a fewfold and lowered power consumption relative to the literature protocols. The procedures also allowed elimination of long-lasting incandescent irradiation (100-500 W). The replacement of NBS by bromine led to a further reduction in the amount of brominating agent. The obtained bromo derivatives were efficiently converted into the corresponding dialdehydes (90-96%), which in turn are useful in materials chemistry.
- Bodzioch, Agnieszka,Owsianik, Krzysztof,Skalik, Joanna,Kowalska, Emilia,Stasiak, Anna,Ró?ycka-Soko?owska, Ewa,Marciniak, Bernard,Ba?czewski, Piotr
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p. 3509 - 3514
(2016/10/17)
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- Four- and Sixfold Tandem-Domino Reactions Leading to Dimeric Tetrasubstituted Alkenes Suitable as Molecular Switches
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A highly efficient palladium-catalyzed fourfold tandem-domino reaction consisting of two carbopalladation and two C-H-activation steps was developed for the synthesis of two types of tetrasubstituted alkenes 3 and 6 with intrinsic helical chirality starting from substrates 1 and 4, respectively. A sixfold tandem-domino reaction was also developed by including a Sonogashira reaction. 20 compounds with different substitution patterns were prepared with yields of up to 97%. Structure elucidation by X-ray crystallography confirmed helical chirality of the two alkene moieties. Photophysical investigations of some of the compounds showed pronounced switching properties through light-controlled changes of their stereochemical configuration.
- Tietze, Lutz F.,Waldecker, Bernd,Ganapathy, Dhandapani,Eichhorst, Christoph,Lenzer, Thomas,Oum, Kawon,Reichmann, Sven O.,Stalke, Dietmar
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p. 10317 - 10323
(2015/09/01)
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- Meta-B-entacenes: New polycyclic aromatics incorporating two fused borepin rings
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The synthesis of new boron-containing acenes (meta-B-entacenes) is reported. These compounds exhibit slightly non-planar core geometries with blue-shifted spectral properties and more negative electrochemical reduction potentials relative to known para is
- Levine, David R.,Caruso, Anthony,Siegler, Maxime A.,Tovar, John D.
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supporting information; experimental part
p. 6256 - 6258
(2012/07/27)
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