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The reactivity of Pd-PEPPSI (Pyridine, Enhanced, Precatalyst, Preparation, Stabilization, and Initiation) precatalysts in the Stille-Migita cross-coupling reaction between heteroaryl stannanes and aryl or heteroaryl halides was evaluated. In general, Pd-PEPPSI-IPent (IPent=diisopentylphenylimidazolium derivative) demonstrated high efficiency over a variety of challenging aryl or heteroaryl halides with thiophene-, furan-, pyrrole-, and thiazole-based organostannanes when compared with Pd-PEPPSI-IPr (IPr=diisopropylphenylimidazolium derivative). The transformations proceeded at appreciably lower temperatures (30-80 degrees C) than triarylphosphine-based Pd catalysts, improving the scope of this useful carbon-carbon bond-forming process.
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http://dx.doi.org/10.1002/chem.200903337 | DOI Listing |
Molecules
July 2020
CNR-Istituto di Chimica dei Composti Organometallici (CNR-ICCOM), Via Madonna del Piano, 10, 50019 Sesto Fiorentino, Italy.
A new series of symmetrical organic dyes containing an indigo central core decorated with different electron donor groups have been prepared, starting from Tyrian Purple and using the Pd-catalyzed Stille-Migita coupling process. The effect of substituents on the spectroscopic properties of the dyes has been investigated theoretically and experimentally. In general, all dyes presented intense light absorption bands, both in the blue and red regions of the visible spectrum, conferring them a bright green color in solution.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2020
Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany.
The heteroleptic dirhodium paddlewheel catalyst 7 with a chiral carboxylate/acetamidate ligand sphere is uniquely effective in asymmetric [2+1] cycloadditions with α-diazo-α-trimethylstannyl (silyl, germyl) acetate. Originally discovered as a trace impurity in a sample of the homoleptic parent complex [Rh ((R)-TPCP) ] (5), it is shown that the protic acetamidate ligand is quintessential for rendering 7 highly enantioselective. The -NH group is thought to lock the ensuing metal carbene in place via interligand hydrogen bonding.
View Article and Find Full Text PDFChembiochem
March 2017
Université Paris-Sud, CNRS, BioCIS-UMR 8076, Laboratoire CoSMIT, Equipe Labellisée Ligue Contre Le Cancer, LabEx LERMIT, Faculté de Pharmacie, 5 rue J.-B. Clément, Châtenay-Malabry, 92296, France.
New applications of Pd-catalyzed coupling reactions (Suzuki-Miyaura, Sonogashira, and Stille-Migita coupling) for post-conjugation of nucleic acids have been developed recently. Breakthroughs in this area might now pave the way for the development of sophisticated DNA probes, which might be of great interest in chemical biology, nanotechnology, and bioanalysis, as well as in diagnostic domains.
View Article and Find Full Text PDFOrg Biomol Chem
January 2015
Organic and Biomolecular Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, India.
This article reported the synthesis of fully functionalized aglycone of lycoperdinoside A and B. Pd-catalyzed Stille-Migita cross coupling between E-vinyl iodide 6 and E-vinyl stannane 23 established the highly substituted E,E-diene unit present in lycoperdinoside A and B. The other two Z-olefins present in the molecule were introduced by means of cis-selective Horner-Wadsworth-Emmons reaction with Still-Gennari phosphonate.
View Article and Find Full Text PDFChemistry
December 2014
Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg.
An optimized catalyst system of [Pd2 (dba)3 ] and AsPh3 efficiently catalyzes the Stille reaction between a diverse set of functionalized stannanes and halogenated mono-, di- and oligonucleotides. The methodology allows for the facile conjugation of short and long nucleic acid molecules with moieties that are not compatible with conventional chemical or enzymatic synthesis, among them acid-, base-, or fluoride-labile protecting groups, fluorogenic and synthetically challenging moieties with good to near-quantitative yields. Notably, even azides can be directly introduced into oligonucleotides and (deoxy)nucleoside triphosphates, thereby giving direct access to "clickable" nucleic acids.
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