scholarly journals Preparation and Diels–Alder/cross coupling reactions of a 2-diethanolaminoboron-substituted 1,3-diene

Author(s):  
Liqiong Wang ◽  
Cynthia S Day ◽  
Marcus W Wright ◽  
Mark E Welker

A 2-diethanolamine boronyl substituted 1,3-diene has been synthesized in high yield and characterized spectroscopically as well as by X-ray crystallography. This diene has then subsequently been used in a number of fast, high yielding Diels–Alder/cross coupling reactions.

2015 ◽  
Vol 11 ◽  
pp. 2171-2178 ◽  
Author(s):  
Johnathon Yau ◽  
Kaarel E Hunt ◽  
Laura McDougall ◽  
Alan R Kennedy ◽  
David J Nelson

Two new nickel catalysts have been prepared using a convenient procedure where nickelocene, the NHC·HBF4 salts, and [Et4N]Cl were heated in THF using microwave irradiation. The resulting [NiCl(Cp)(NHC)] complexes are air- and moisture stable in the solid state, and represent two new members of this valuable and practical class of nickel catalysts. The new species were fully characterised using methods including NMR spectroscopy and X-ray crystallography. When tested in model Suzuki–Miyaura cross-coupling reactions, these complexes were found to be active for the cross-coupling of aryl bromides and aryl chlorides.


Author(s):  
Tilman Lechel ◽  
Irene Brüdgam ◽  
Hans-Ulrich Reissig

A series of trifluoromethyl-substituted 3-alkoxypyridinol derivatives has been deprotected to furnish pyridine-3,4-diol derivatives in good yields. The X-ray crystal structure analysis proved that a 1:1 mixture of pyridine-3,4-diols and their pyridin-4-one tautomers exist in the solid state. Subsequent conversion into bis(perfluoroalkanesulfonate)s were smoothly achieved. The obtained compounds were used as substrates for palladium-catalyzed coupling reactions. Fluorescence measurements of the biscoupled products showed a maximum of emission in the violet region of the spectrum.


Synthesis ◽  
2018 ◽  
Vol 50 (10) ◽  
pp. 2009-2018
Author(s):  
Jan-Hendrik Lamm ◽  
Philipp Niermeier ◽  
Leif Körte ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
...  

An easy access to 1,8-dichloro-10-(ethynyl)anthracene is reported, which is widely applicable for building up rigid linkers between two 1,8-dichloroanthracene units. For this, 1,8-dichloroanthren-10(9H)-one was reacted with ethynylmagnesium bromide in the presence of CeCl3; the yield was 65%. This building block was used as a substrate in (cross-)coupling reactions and some examples of linked 1,8-dichloroanthracen-10-yls (e.g., 1,8-bis[(1,8-dichloroanthracen-10-yl)-ethynyl]naphthalene or 1,2-bis[(1,8-dichloroanthracen-10-yl)ethynyl]-benzene) were synthesized in good to moderate yields. Linked 1,8-dichloroanthracen-10-yl derivatives were also synthesized by cross-coupling reactions using 10-bromo-1,8-dichloroanthracene and doubly ethynyl-substituted substrates. Linkers between the 1,8-dichloroanthracene units were: butadiynediyl, dimethylsilyldiethynyl, octa-1,7-diyne-1,8-diyl, propane-1,3-diylbis(dimethylsilyl)diethynyl, benzene-1,2-diethynyl, naphthalene-1,8-diyldiethynyl, and anthracene-1,8-diyldiethynyl. The new anthracene compounds were characterized by NMR spectroscopy, high-resolution mass spectrometry, and, in part, by X-ray diffraction experiments.


Author(s):  
Thuy Luong Thi Thu ◽  
Ngan Nguyen Bich ◽  
Hien Nguyen ◽  
Luc Van Meervelt

Facile synthetic routes for three 4-substituted 2,2′-bipyridine derivatives, 4-[2-(4-methylphenyl)ethynyl]-2,2′-bipyridine, C19H14N2, (I), 4-[2-(pyridin-3-yl)ethynyl]-2,2′-bipyridine, C17H11N3, (II), and 4-(indol-4-yl)-2,2′-bipyridine, C18H13N3, (III),viaSonogashira and Suzuki–Miyaura cross-coupling reactions, respectively, are described. As indicated by X-ray analysis, the 2,2′-bipyridine core, the ethylene linkage and the substituents of (I) and (II) are almost planar [dihedral angles between the two ring systems: 8.98 (5) and 9.90 (6)° for the two molecules of (I) in the asymmetric unit and 2.66 (14)° for (II)], allowing π-conjugation. On the contrary, in (III), the indole substituent ring is rotated significantly out of the bipyridine plane [dihedral angle = 55.82 (3)°], due to steric hindrance. The crystal packings of (I) and (II) are dominated by π–π interactions, resulting in layers of molecules parallel to (30-2) in (I) and columns of molecules along theaaxis in (II). The packing of (III) exhibits zigzag chains of molecules along thecaxis interacting through N—H...N hydrogen bonds and π–π interactions. The contributions of unknown disordered solvent molecules to the diffraction intensities in (II) were removed with the SQUEEZE [Spek (2015).Acta Cryst.C71, 9–18] algorithm ofPLATON. The given chemical formula and other crystal data do not take into account these solvent molecules.


2015 ◽  
Vol 70 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Atena B. Şolea ◽  
Marian Olaru ◽  
Cristian Silvestru ◽  
Ciprian I. Raţ

AbstractSubstituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH [R=2,4,6-Me3C6H2 (1), Me5C6 (2)] were synthesized using Kumada cross-coupling reactions between 2,4,6-I3C6H2OH and the corresponding Grignard reagent. Both compounds were structurally characterized in solution by 1H and 13C NMR spectroscopy and HRMS. The molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction.


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