Nickel-Catalyzed Diastereoselective Alkyl–Alkyl Kumada Coupling Reactions

Bimetallic oxidative addition involving radical intermediates in nickel-catalyzed alkyl-alkyl Kumada coupling reactions.

Many nickel-based catalysts have been reported for cross-coupling reactions of nonactivated alkyl halides. The mechanistic understanding of these reactions is still primitive. Here we report a mechanistic study of alkyl-alkyl Kumada coupling catalyzed by a preformed nickel(II) pincer complex ([(N2N)Ni-Cl]). The coupling proceeds through a radical process, involving two nickel centers for the ox...

Nickel-Catalyzed Coupling Reactions of Alkenes.

Several reactions of simple, unactivated alkenes with electrophiles under nickel(0) catalysis are discussed. The coupling of olefins with aldehydes and silyl triflates provides allylic or homoallylic alcohol derivatives, depending on the supporting ligands and, to a lesser extent, the substrates employed. Reaction of alkenes with isocyanates yields N-alkyl acrylamides. In these methods, alkenes...

Nickel (0) Catalyzed Kumada Chain Transfer Polycondensation

Nickel/bis(oxazoline)-catalyzed asymmetric Kumada reactions of alkyl electrophiles: cross-couplings of racemic alpha-bromoketones.

The first asymmetric Kumada reactions of alkyl electrophiles are described, specifically, cross-couplings of racemic alpha-bromoketones with aryl Grignard reagents. Several features of this investigation are of interest. First, the couplings proceed at remarkably low temperature (-40 or -60 degrees C), which enables the asymmetric synthesis of racemization-prone alpha-arylketones. Second, dialk...

Towards nickel boride catalyzed C-C coupling reactions

This thesis focuses on the study of nickel boride as a catalyst in various coupling reactions. The nickel boride catalyst was investigated in three different coupling reactions, the experiments aimed at understanding the activity and catalytic properties of nickel boride. We successfully synthetized the nickel boride catalyst, alongside with the cobalt and iron boride. Different methods of prep...