Reactions of activated organonickel σ-complexes with elemental (white) phosphorus

Photoinduced Nickel-Catalyzed Selective N-Demethylation of Trialkylamines Using C(sp2)-Bromides as HAT Reagents

N-Demethylation of trialkylamines is a useful transformation, but typically requires harsh reaction conditions and stepwise procedures, as well as judicious protection of labile functional groups. Herein we report a mild, catalytic approach for the demethylation of trialkylamines by utilizing photoinduced nickel catalysis wherein C(sp2)-bromides serve as hydrogen-atom transfer (HAT) reagents. This method achieves direct demethylation of trialkylamines with wide functional group compatibility, making it highly suitable for late-stage derivatization of complex molecules. Mechanistic investigations provide evidence that C(sp2) radicals generated via photoinduced Ni-C(sp2) bond homolysis are involved in hydrogen atom abstraction from trialkylamines. Utilizing steric control of the C(sp2)-bromides, our HAT approach achieves demethylation with excellent site selectivity in the presence of benzyl-substituted amines, which is complementary to the selectivity of classical approaches that afford debenzylation product instead.

Nickel Complexes in C‒P Bond Formation

This review is a comprehensive account of reactions with the participation of nickel complexes that result in the formation of carbon-phosphorus (C‒P) bonds. The catalytic and non-catalytic reactions with the participation of nickel complexes as the catalysts and the reagents are described. The various classes of starting compounds and the products formed are discussed individually. The several putative mechanisms of the nickel catalysed reactions are also included, thereby providing insights into both the synthetic and the mechanistic aspects of this phosphorus chemistry.

Hydrogenation reaction pathways in chemistry of white phosphorus

Approaches for preparation of P–H bond containing derivatives directly from white phosphorus are summarized in this microreview. Transfer hydrogenation of P4 involving the activation and reaction of white phosphorus in the coordination sphere of transition metal complexes is a convenient and powerful route to the hydrogenated compounds. Electrochemical methods have also become popular in modern synthetic chemistry; these provide easy access to highly reactive intermediates, which can be selectively generated in situ and used for subsequent synthetic processes. These electrochemical routes provide efficient and environmentally safe methods for preparation of phosphorus derivatives bearing P–H bond. The mechanisms of the proposed processes and the nature of the intermediates formed in the overall electrochemical process are disclosed. The methods elaborated operate under the principals of “green chemistry” and can be considered as efficient alternatives to some classical pathways.

Electrochemical methods for synthesis of organoelement compounds and functional materials

The new efficient and environmentally safe methods for preparation of various classes of organic and organoelement compounds, including organonickel sigma-complexes and organophosphorus compounds bearing P–C bonds have been created using the electrochemical methods. The synthetic application of the elaborated techniques towards the process of formation of new carbon-carbon, carbon-metal and carbon-phosphorus bonds are discussed. The mechanisms of the proposed processes and the nature of the formed in the overall electrochemical process intermediates are disclosed. The elaborated methods operated in the principals of “green chemistry” can be considered as an efficient alternative to some classical methods for preparation of active catalysts, biologically active molecules and new polynuclear complexes displaying practically useful properties.

Rhodium-catalyzed P–P bond exchange reaction of diphosphine disulfides

A rhodium-catalyzed exchange reaction of diphosphine disulfides, a diphosphine oxide, and a diphosphine is developed. Various symmetric diphosphine disulfides containing alkyl and phenyl groups are exchanged.