45267
2016
2016
eng
2972
2982
11
article
Wiley-VCH
Weinheim
1
--
--
--
Styrylsulfonates and -Sulfonamides through Pd-Catalysed Matsuda-Heck Reactions of Vinylsulfonic Acid Derivatives and Arenediazonium Salts
Arene diazonium salts undergo Matsuda-Heck reactions with vinylsulfonates and -sulfonamides to give styrylsulfonic acid derivatives in high to excellent yields and with high to excellent selectivities. By quantifying the evolution of nitrogen over time in a gas-meter apparatus, the reactivities of ethylvinylsulfonate and the benchmark olefin methyl acrylate were compared for an electron-rich and an -deficient arene diazonium salt. Tertiary sulfonamides react in Matsuda-Heck couplings with high conversions, but require long reaction times, which prevents the determination of kinetic data through the measurement of nitrogen evolution. Secondary sulfonamides were found to be unreactive. From these results, the following order of reactivity could be deduced: H2C=CHCO2Me > H2C=CHSO2OEt > H2C=CHSO2N(Me)Bn >> H2C=CHSO2NHBn. Through the Matsuda-Heck coupling of 5-indolyldiazonium salt and a tertiary vinylsulfonamide, the synthesis of the C-5-substituted indole part of the antimigraine drug naratriptan was accomplished in high yield.
European journal of organic chemistry
10.1002/ejoc.201600469
1434-193X
1099-0690
wos2016:2019
WOS:000379755600010
Schmidt, B (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany., bernd.schmidt@uni-potsdam.de
importub
2020-03-22T17:07:01+00:00
filename=package.tar
4a9d2442cd3db38f22b38a85030a53df
Bernd Schmidt
Felix Wolf
Heiko Brunner
eng
uncontrolled
Homogeneous catalysis
eng
uncontrolled
Cross-coupling
eng
uncontrolled
Palladium
eng
uncontrolled
Sulfonamides
eng
uncontrolled
Alkenes
eng
uncontrolled
Drug design
Institut für Chemie
Referiert
Import
37799
2014
2014
eng
2952
2960
9
18
article
Wiley-VCH
Weinheim
1
--
--
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Efficient palladium(II) precatalysts bearing 4,5-dicyanoimidazol-2-ylidene for the Mizoroki-Heck reaction
The new N-heterocyclic carbene (NHC) complex [PdCl2{(CN)(2)IMes}(PPh3)] (2) ({(CN)(2)IMes}: 4,5-dicyano-1,3-dimesitylimidazol-2-ylidene) and the NHC palladacycle [PdCl(dmba){(CN)(2)IMes}] (3) (dmba: N,N-dimethylbenzylamine) have been synthesized by thermolysis of 4,5-dicyano-1,3-dimesityl-2-(pentafluorophenyl) imidazoline (1) in the presence of suitable palladium(II) precursors. The acyclic complex 2 was formed by ligand exchange using the mononuclear precursor [PdCl2(PPh3)(2)] and the palladacycle 3 was formed by cleavage of the dinuclear chloro-bridged precursor [Pd(mu-Cl)(dmba)](2). The new NHC precursor 1-benzyl-4,5-dicyano-2-(pentafluorophenyl)-3-picolylimidazoline (5) was formed by condensation of pentafluorobenzaldehyde with N-benzyl-N'-picolyldiaminomaleonitrile (4). The NHC palladacycle [PdCl2{(CN)(2)IBzPic}] (6) ({(CN)(2)IBzPic}: 1-benzyl-4,5-dicyano-3-picolylimidazol-2-ylidene) was prepared by in situ thermolysis of 5 in the presence of [PdCl2(PhCN)(2)]. The three palladium(II) complexes were characterized by NMR and IR spectroscopy, mass spectrometry and elemental analysis. In addition, the molecular structures of 2 and 3 were determined by X-ray diffraction. The pi-acidity of (CN)(2)IBzPic was compared with (CN)(2)IMes and perviously reported pi-acidic imidazol-2-ylidenes by NBO analysis. The Mizoroki-Heck (MH) reactions of various aryl halides with n-butyl acrylate were performed in the presence of complexes 2, 3 and 6. The new precatalysts showed high activity in the MH reactions giving good-to-excellent product yields with 0.1 mol-% pre-catalyst. The nature of the catalytically active species of 2, 3 and 6 was investigated by poisoning experiments with mercury and transmission electron microscopy. It was found that palladium nanoparticles formed from the precatalysts were involved in the catalytic process.
European journal of inorganic chemistry : a journal of ChemPubSoc Europe
10.1002/ejic.201402040
1434-1948
1099-0682
wos:2014
WOS:000338033200009
Holdt, HJ (reprint author), Univ Potsdam, Dept Inorgan Chem, Karl Liebknecht Str 24-25, D-14476 Golm, Germany., Holdt@uni-potsdam.de
Heiko Baier
Philipp Metzner
Thomas Körzdörfer
Alexandra Kelling
Hans-Jürgen Holdt
eng
uncontrolled
Homogeneous catalysis
eng
uncontrolled
Palladium
eng
uncontrolled
Cross coupling
eng
uncontrolled
Carbene ligands
Institut für Chemie
Referiert