Alexander S. Peregudov

Mechanistic Investigation of the Asymmetric Addition of Trimethylsilyl Cyanide to Aldehydes Catalysed by Dinuclear Chiral (Salen)titanium Complexes

Titanium complexes 1 derived from chiral salen ligands are highly active precatalysts for the asymmetric addition of trimethylsilyl cyanide to aldehydes and ketones. Based on spectroscopic studies and the identification of adducts between complexes 1 and carbonyl compounds or trimethylsilyl cyanide, a catalytic cycle which explains the origin of the asymmetric induction is proposed. Kinetics studies have been carried out, the results of which are consistent with the proposed catalytic cycle.

New approaches to the synthesis of unsymmetrical diaryl selenides

Abstract Unsymmetrical diaryl selenides PhSeAr were obtained by the palladium catalysed reactions of aryl (heteroaryl) iodide or triflate with Bu 3 SnSePh in high yields. The same compounds can be obtained by the non-catalytic reactions of Bu 3 SnSePh with ArN 2 BF 4 or (ArN 2 ) 2 ZnCl 4 .

Facile preparation of amine and amino acid adducts of [60]fullerene using chlorofullerene C60Cl6 as a precursor.

We report a general synthetic approach to the preparation of highly functionalized amine and amino acid derivatives of [60]fullerene starting from readily available chlorofullerene C(60)Cl(6). The synthesized water-soluble amino acid derivative of C(60) demonstrated pronounced antiviral activity, while the cationic amine-based compound showed strong antibacterial action in vitro.

Copper(I)-catalyzed arylselenylation of aryl bromides and iodides

A new protocol to prepare unsymmetrical diarylselenides using the reaction of aryl bromides and iodides with easily available Bu3SnSeAr catalyzed by Cu(I) complexes under rather mild conditions and with a very high yield is described.

Self-Assembly of Thiophene- and Furan-Appended Methanofullerenes with Poly(3-Hexylthiophene) in Organic Solar Cells

Novel fullerene derivatives bearing thiophene and furan residues were synthesized and studied as electron acceptor materials in bulk heterojunction organic solar cells, together with poly(3-hexylthiophene) (P3HT) as the donor polymer. Some compounds showed large nanomorphological inhomogenities in blends with P3HT; in particular, clusters with dimensions in the range of 100-1000 nm were formed. However, some blends that showed such large clusters yielded at the same time high power conversion efficiencies in photovoltaic devices, approaching 3.7 %. This is in sharp contrast with previously studied systems, in which a substantial phase separation always resulted in a poor photovoltaic performance. We assume that the attachment of thienyl or furyl groups to the fullerene cage results in a certain ordering of the designed fullerene derivatives I-IX with P3HT in photoactive blends. Both the fullerene derivative and P3HT might assemble via pi-pi stacking of the thiophene units to form the nanostructures observed in the films by optical and atomic force microscopy. The presence of ordered donor and acceptor counterparts in these nanostructures results in superior photovoltaic device operation.

A Comparative PMR study of Exchange reactions in organo- Mercury, -TIN and -LEAD derivatives of some thiols

Abstract Metal—proton and metal—metal exchange reactions have been studied by PMR for thiophenol, 2-methylthiophenol, 2,6-dimethylthiophenol, benzyl mercaptan and their C 6 H 5 HG, (C 6 H 5 ) 3 Sn and (C 6 H 5 ) 3 Pb derivatives in chlorobenzene and pyridine solutions. In chlorobenzene the metal—metal exchange has been found to proceed in many cases at a greater rate than the metal—proton type, the exchange mobility of hydrogen and organometallic groups in chlorobenzene increasing in the order (C 6 H 5 ) 3 Sn 6 H 5 ) 3 Pb 6 H 5 Hg. In the case of the (C 6 H 5 ) 3 Sn and (C 6 H 5 ) 3 Pb groups, pyridine accelerates the metal—proton exchange to a greater extent than the metal—metal exchange. The influence of various factors on the exchange reactions has been studied Analysis of the experimental findings and literature data has led to the conclusion that most probably the mechanism of the exchange reactions involves an associative pathway, the ease of exchange being mainly determined by the ability of the migrating group to form a cyclic transition state with delocalized bonds. The data on the exchange equilibria of the organometallic derivatives of 2-methylthiophenol and 2,6-dimethylthiophenol with thiophenol and its derivatives demonstrate that the C 6 H 5 HgS, (C 6 H 5 ) 3 SnS and (C 6 H 5 ) 3 PbS groups have equal steric requirements when involved in non-bonded interactions with o -methyl substituents.

Cyclotetrasiloxanetetrols with methyl groups at silicon: isomers all-cis- and cis-trans-cis-[MeSi(O)OH](4).

1,3,5,7-Tetramethyl-1,3,5,7-tetrahydroxycyclotetrasiloxane has been synthesized in good yield from tetrapotassium tetramethylcyclotetrasiloxanolate. Methods for isolation of all-cis-isomer I and cis-trans-cis-isomer II as the only crystalline product have been developed. Both isomers have been characterized by single-crystal X-ray diffraction analysis (XRD), elemental analysis, NMR ((1)H, (13)C, (29)Si), and IR. The stability of these compounds in solutions and the solid state has been investigated.

Diastereoselective Synthesis of Anti‐β‐Substituted α‐Aminobutanoic Acids via Michael Addition Reactions of Nucleophiles to New Chiral Ni(II) Complexes of Dehydroaminobutanoic Acid

Abstract New chiral NiII complex of the dehydroaminobutanoic acid Schiff base with (S)‐N‐(2‐benzoylphenyl)‐1‐(3,4‐dichlorbenzyl)pyrrolidyl‐2‐carboxamide (CPB) was synthesized and tested as electrophile component in the asymmetric Michael addition reactions with nucleophiles (imidazole, benzylamine, methoxy ion, ethoxy ion). The method of the asymmetric synthesis of β‐substituted (S)‐α‐amino acids with high d.e > 80% was developed.

Hydrolytic condensation of trialkoxysilanes in the presence of alkali metal and copper(II) ions. Influence of the reaction conditions on the structure of Cu/M organosiloxanes

The formation of polyhedral copper/sodium(potassium) organosiloxanes was examined as a result of hydrolytic condensation of organotrialkoxysilanes in the presence of copper(ii) and sodium or potassium ions. High selectivity of the synthesis of copper/sodium(potassium) organosiloxanes having desired structures can be achieved by choosing the reaction conditions.

Halo-substituted (S)-N-(2-benzoylphenyl)-1-benzylpyrolidine-2-carboxamides as new chiral auxiliaries for the asymmetric synthesis of (S)-α-amino acids

The synthesis of new chiral auxiliaries (S)-N-(2-benzoylphenyl)-1-(3,4-dichlorobenzyl)-pyrrolidine-2-carboxamide (1a), (S)-N-(2-benzoylphenyl)-1-(pentafluorobenzyl)pyrrolidine-2-carboxamide (1b), and (S)-N-(2-benzoylphenyl)-1-(4-isopropoxytetrafluorobenzyl)pyrrolidine-2-carboxamide (1c) and their application in the asymmetric synthesis of amino acids using NiII complexes of their Schiffs bases with alanine and glycine are described. Compound 1a is particularly appropriate for highly stereoselective synthesis of α-methyl-α-amino acids with high enatiomeric purity (ee >95%).