New Pd–NHC-complexes for the Mizoroki–Heck reaction

Chiral bisimidazolium salts derived from amino acids and their palladium(II)- and platinum(II)-biscarbene complexes

“…We modified the published procedure for the preparation of the imidazoles 1a-j (without previous esterification of the L-amino acid) by substituting HCl/MeOH by SOCl 2 /ROH, which is more convenient and turned out to be superior to the one-pot imidazole synthesis [12,53] where glyoxal and paraformaldehyde react with the amino acid ester hydrochloride in methanol solution.…”

“…Especially bidentate or tridentate NHC-ligands have shown their potential in many applications, for example C-C coupling reactions [10][11][12][13][14][15] or CH activation [16,17]. The first chiral Nheterocyclic carbene structures were published by Herrmann [18] and Enders [19] in 1996.…”

Maßgeschneiderte Aryl‐Alkyl‐substituierte ionische Flüssigkeiten (TAAILs) – die nächste Generation ionischer Flüssigkeiten

“…Aus dem Bereich der Flüssigkristallforschung erschien kürzlich eine Publikation, die über den vorteilhaften Effekt von Phenyl-und Biphenylgruppen auf die mesomorphen Eigenschaften ionischer Flüssigkristalle berichtete. [5] Die gegenwärtig wichtigste Klasse der ILs sind Imidazoliumsalze, die generell sp 3 [6] Wir untersuchen Imidazolium-basierte Verbindungen als Vorstufen zur Synthese von NHC-Metallkomplexen; [7] NHCs (N-heterocyclische Carbene) sind eine sehr interessante Klasse von Liganden in der homogenen Katalyse. [8] Sie sind in der Regel stabiler als die Phosphinliganden und wurden bisher als s-Donorliganden mit vernachlässigbarem p-Anteil beschrieben.…”

Synthesis of Precursor Imidazolium Salts for the Synthesis of N-Heterocyclic Carbines Used as Ligands for the Enantioselective Preparation of Heterosteroids Compounds

“…A et al,3 NHCs are playing an increasingly important role in major areas of organometallic, organic, and polymer chemistry 4 . Their metal complexes are known as extremely versatile and stable catalysts for a wide range of reactions including C-C coupling reactions [5][6][7][8][9][10][11] , olefin metathesis [12][13][14][15] , hydroformylation [16][17] & polymirization reactions [18][19] . The imidazolium salts 1-phenyl-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)-1H-imidazol-3-ium bromide (4), and 1-(pyrimidin-2-yl)-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)propyl)-1H-imidazol-3-ium bromide (5) were respectively prepared by coupling reaction of the precursors 1-phenyl-1H-imidazole (1) and 2-(1H-imidazol-1-yl)pyrimidine (2) with 2-(3-Bromopropyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(3).…”