Sofia Strekalova

One-stage synthesis of FcP(O)(OC2H5)2 from ferrocene and α-hydroxyethylphosphonate

A new approach is proposed for ferrocene phosphorylation using α-hydroxylalkylphosphonate as a “masked” phosphorylating agent, by electrochemical reduction of a ferrocene and (Me)2C(OH)P(O)(OC2H5)2 mixture at −50 °C. The method makes it possible to obtain the product of diethyl ferrocenyl phosphonate with a high yield (87–89%) and 100% conversion of the initial phosphonate in one stage. It is evidenced with experiments that ferrocene reduction is carried out with preservation of the iron charge in the ferrocene fragment and with the formation of a cyclopentadienyl ligand radical anion at −3.3 V ref. Ag/AgCl (at −50 °C).

Electrochemical oxidative phosphonation of azoles

GRAPHICAL ABSTRACT ABSTRACT Metal-catalyzed electrochemical oxidative phosphonation of hetaryl-azoles (benzoxazoles, benzothiazole and others) with dialkyl-H-phosphonate was developed. Joint electrochemical oxidation of azoles and dialkyl-H-phosphonate mixtures in the presence of catalytic quantities of salts of transition metals at room temperature affords the desired 2-substituted azoles. Palladium, nickel and silver salts were tested as catalysts.

Electrooxidative phosphorylation of coumarins by bimetallic catalytic systems Ni(II)/Mn(II) or Co(II)/Mn(II)

GRAPHICAL ABSTRACT ABSTRACT The phosphorylation of coumarins (coumarin, 6-methylcoumarin, 7-methylcoumarin) by catalytic oxidation of a mixture of coumarins and diethyl phosphite (1:1) in electrochemical mild conditions (room temperature and normal pressure) using bimetallic catalyst systems, MnCl2bpy/Ni(BF4)2bpy or MnCl2bpy/CoCl2bpy(bpy-2,2′-bipyridine) was realized.

Various ways of C-P bonds formation via selective electrochemical phosphorylation of aromatic C-H bonds

GRAPHICAL ABSTRACT ABSTRACT Principal achievements and modern trends in the development of new methods of electrocatalytic phosphorylation are analyzed and generalized. Possibilities and advantages of the electrochemical preparation of phosphorus compounds are demonstrated. The attention is focused on the CH-substitution of aromatic substrates by electrochemical reactions.

Direct phosphorylation of pyridine in the presence of Ni(BF4)2bpy and CoCl2bpy metal complexes

GRAPHICAL ABSTRACT ABSTRACT A new approach to the phosphorylation of pyridine with diethyl-H-phosphonate in the presence of metal complexes Ni(BF4)2bpy and CoCl2bpy is described. The reaction is carried out in electrochemical mild conditions (room temperature, normal pressure) and the ratio of the reagents is 1: 1. This method forms a pyridylphosphonate with high yield (up to 90%) and 100% conversion of H-phosphonate.

Cobalt-Catalyzed Green Cross-Dehydrogenative C(sp 2 )-H/P-H Coupling Reactions

Joined electrolysis of arenes (benzene or coumarin derivatives) and diethyl-H-phosphonate (EtO)2P(O)H in the presence of [CoCl2(bpy)] catalyst (5%) in an ethanol-aqueous solution in reductive conditions allows obtaining the desired products in a single step by aromatic C–H bonds phosphonation with yields up to 70%. The only by-product is hydrogen; the reaction proceeds at room temperature and does not require specially added reducing agents and oxidants or other initiators. Radical mechanism has been confirmed for the catalytic reaction proceeding via bicobalt phosphonates with Co–P bond, the structure of which also has been identified.

Silica-supported silver nanoparticles as an efficient catalyst for aromatic C-H alkylation and fluoroalkylation

The efficient catalysis of oxidative alkylation and fluoroalkylation of aromatic C-H bonds is of paramount importance in the pharmaceutical and agrochemical industries, and requires the development of convenient Ag0-based nano-architectures with high catalytic activity and recyclability. We prepared Ag-doped silica nanoparticles (Ag0/+@SiO2) with a specific nano-architecture, where ultra-small sized silver cores are immersed in silica spheres, 40 nm in size. The nano-architecture provides an efficient electrochemical oxidation of Ag+@SiO2 without any external oxidant. In turn, Ag+@SiO2 5 mol% results in 100% conversion of arenes into their alkylated and fluoroalkylated derivatives in a single step at room temperature under nanoheterogeneous electrochemical conditions. Negligible oxidative leaching of silver from Ag0/+@SiO2 is recorded during the catalytic coupling of arenes with acetic, difluoroacetic and trifluoroacetic acids, which enables the good recyclability of the catalytic function of the Ag0/+@SiO2 nanostructure. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times upon electrochemical regeneration. The use of the developed Ag0@SiO2 nano-architecture as a heterogeneous catalyst facilitates aromatic C-H bond substitution by alkyl and fluoroalkyl groups, which are privileged structural motifs in pharmaceuticals and agrochemicals.