Elisa Hernandez

Nickel(0)-katalysierte bildung von carbocyclischen amiden aus α,ω-dienen und phenylisocyanat

Abstract Phenyl isocyanate reacts readily with 1,5-hexadiene and a (ligand)nickel(0) system forming two regioisomeric azanickela-five ring complexes by 1 1 CC-coupling at −10°C. On warming, subsequent reactions eventually yield five-membered carbocyclic amides by intramolecular cyclisation. It has been found that by using a special experimental procedure - continuous slow addition of the isocyanate to a solution containing the diene and nickel(0) complexes - the reaction can be carried out catalytically. With this approach, 1,6-heptadiene gives both a carbocyclic and an acyclic amide. The catalytic cycles are presented and discussed in detail.

CC-verknüpfung von styrol mit isocyanaten an nickel(0), eine katalytische synthese von zimtsäureamiden

Abstract Isocyanates react with styrene at ligand-nickel(0) systems by 1/1 CC coupling giving azanickelacyclopentanones. The nickela five-membered rings obtained in this way are characterized spectroscopically, and their reaction modes are described. Depending on the ligands and special reaction conditions it is shown that with continuous, slow addition of the isocyanate to the solution of styrene and the Lig-Ni0 starting complex catalytic formation of cinnamanilide occurs.

Stöchiometrische und katalytische CC-verknüpfungen zwischen 1,3-butadien und phenylisocyanat an nickel(0)-komplexen

Abstract The CC coupling of 1,3-butadiene with phenyl isocyanate at nickel(0) systems is ligand-dependent. Basic phosphanes such as triethyl- or tricyclohexylphosphane induce a stoichiometric 1 1 CC-coupling reaction yielding azanickela complexes. Triphenylphosphane, on the other hand, leads to a catalytic reaction. Catalysis is initiated by 2 1 coupling, which, after intramolecular cyclisation finally yields carbocyclic five-ring amides. Some special features are listed and the reaction mechanisms are discussed.

Nickel(0)-katalysierte Synthese von Crotonsäureanilid aus Propen und Phenylisocyanat

Abstract Isocyanates react with propene at ligand-nickel(0) systems by 1/1 CC coupling to give two isomer azanickelacyclopentanones. The nickela five-membered rings thus obtained were characterized and their reaction modes are described. Depending on the ligand present and under special reaction conditions, with continuous, slow addition of the isocyanate to a solution of propene and the (lig)Ni 0 starting complex, that there is catalytic formation of crotonic acid anilide.

Intermolekulare CC-verknüpfung von azanickelacyclopentanonen, α,ω-disäureamide aus alkenen und phenylisocyanat

Abstract The reaction mode of the nickela five-membered ring complexes, prepared from phenyl isocyanate and the alkenes ethene, propene and styrene at (Lig)Ni0 systems, with oxidizing reagents such as FeCl3 and iodine are reported. Depending on the ligands, either unsaturated acid amides are formed or α,ω-diacid amides result by intermolecular CC bond formation. In this way the azanickela seven-membered ring complexes yield linear 1,8-diacid amides.

α, ω-Disäureamide aus 1,2-alkadienen und isocyanaten an nickel(O)-komplexen

Abstract The 5-membered nickelacyclic compounds formed by 1,2-dienes and phenylisocyanates on nickel(O) complexes react with oxidizing agents such as FeCl 3 , iodine or Ce 4+ salts by CC coupling to α, ω-diamides.

Nickel(0) induzierte und katalysierte CC-Verknu¨pfungen von Styrol mit α, ω-Diisocyanaten

Abstract The reaction of 1, 6-Hexamethylenediisocyanate with styrene at the (lig)Ni 0 system (lig = TCP) is dependent on the molar ratio to either the mono- or the bisazanickela 5-rings. Under certain conditions the normally stoichiometric reaction changes into one which is catalytic. In a regioselective C-C coupling reaction N , N′ -(hexanediyl)biscinnamic amide is formed after about 7 catalytic cycles. Spectroscopic and chemical methods were used to identify the structures. Some special features of the C-C coupling reactions and the mechanism of the catalysis are described.

Nickel(0)-catalysed synthesis of unsaturated carboxylic acid anilides from ethene and phenyl isocyanate

The first metal-catalysed synthesis of unsaturated carboxylic acid anilides from ethene and phenyl isocyanates is described; depending on the ligand, temperature, and pressure the anilides of crylides of acrylic and n-pentenoic acid can be formed selectively.