1H and13C NMR spectra of polycyclic compounds

Using 2D¹H and¹³C correlation NMR spectroscopy, all signals in the¹H and¹³C NMR spectra of five stereoisomeric bicyclo[2.2.1]heptadiene trimers, decacyclo[9.9.1.0^2.10.0^3.8.0^4.6.0^5.9.0^12.20.0^13.18.0^14.16.0^15.19]heneicosanes, obtained by Pd-catalyzed codimerization of norbornadiene dimer with quadricyclane followed by homocyclotrimerization of the latter were assigned unambiguously. Independent stereochemical identification of the trimers was performed using data on the nuclear Overhauser effect.     

(2Z)-2,3,4,5,5-Pentachloropenta-2,4-dienic acid as a minor product in the synthesis of 5,5-dimetoxytetrachlorocyclopentadiene from hexachlorocyclopentadiene

Russian Chemical Bulletin - Pentachloropentadienic acid was isolated, apart from the expected 5,5-dimetoxytetrachlorocyclopentadiene, in the reaction of hexachlorocyclopentadiene with potassium...     

Some properties of the operators generated by a derivative of the acoustic double layer potential

We give a formula for calculating a derivative of the acoustic double layer potential and prove boundedness of the operator generated by a derivative in generalized Hölder spaces.     

Synthesis and transformations of metallacycles

A regioselective method for the synthesis of 1,1-dialkylcyclopropanes was developed. The method is based on the reaction of 2,3-dialkyl-1-ethylalumacyclopent-2-enes with an excess of dialkyl sulfates (Me₂SO₄ or Et₂SO₄). A plausible reaction mechanism was suggested. For Part 20, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1092–1095, June, 2000.     

Cycloaddition of diazoketones to [60]fullerene in the presence of the catalytic system Pd(acac)2—PPh3—Et3Al

A method for the selective and efficient synthesis of methanofullerenes by cycloaddition of diazoketones to [60]fullerene in the presence of a three-component catalytic system Pd(acac)₂—PPh₃—Et₃Al has been developed.     

Dzhemilev reaction in the synthesis of five-membered sulfur and selenium heterocycles*

A one-pot methods were developed for the synthesis of five-membered sulfur and selenium heterocycles based on the consecutive cyclometallation of olefins, allenes, and acetylenes using alkyl and haloalkyl derivatives of Al and Mg in the presence of catalytic amounts of titanium and zirconium complexes to give the corresponding alumina- and magnesacarbocycles in situ, which, without further purification, were introduced into reaction with sulfur or selenium, leading to various tetrahydrothiophenes, thiophenes, tetrahydroselenophenes, and selenophenes. * Dedicated to Academician B. A. Trofimov of the Russian Academy of Sciences on the occasion of his seventieth jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 393–403, March, 2009.     

Constructive Method for Solving a Boundary Value Problem with Impedance Boundary Condition for the Helmholtz Equation

We substantiate the collocation method for the singular integral equation of a boundary value problem with impedance condition for the Helmholtz equation. We construct a sequence converging to the exact solution of the original problem and estimate the error.