S. V. Amosova

New Methods for Preparation of Organoselenium and Organotellurium Compounds from Elemental Chalcogens

The review summarizes the results of studies in the field of development of efficient proceduresfor the synthesis of dialkyl chalcogenides, dialkyl dichalcogenides, vinyl and ethynyl chalcogenides, andselenium-, tellurium-, and silicon-containing heterocyclic compounds on the basis of elemental seleniumand tellurium.

Thia-, Aza-, and Selena[3.3.1]bicyclononane Dichlorides: Rates vs Internal Nucleophile in Anchimeric Assistance

Sulfur-, selenium-, and nitrogen-containing compounds bearing leaving groups in the β-position undergo facile substitution chemistry enabled by anchimeric assistance. Here we provide direct comparisons between such systems in the rigid bicyclo[3.3.1]nonane framework easily derived from 1,5-cyclooctadiene. For a series of dichloride electrophiles of this type, the relative reactivities were found to be Se ≫ (alkyl)N > S ≥ (propargyl)N > (phenyl)N, with the reaction rates at the two extremes differing by more than 3 orders of magnitude. For the N-alkyl case, substitution rates were largely independent of the trapping nucleophile but were strongly dependent on solvent, showing that the process is controlled by the formation of the high-energy three-membered cationic intermediate.

Reactions of triads Se8KOHDMSO, Se8KOHDMSO, TeKOHHMPA with acetylenes

Abstract A new general approach to anionic transformations of acetylenes using superbasic media has been developed. It allows series of new reactions which are not undergone by acetylene under conventional conditions. The triads Se8KOHdimethylsulfoxide (DMSO), Se8KOHDMSO, TeKOH-hexamethyl-phosphorictriamide (HMPA) are proposed as new effective reagents for the preparation of unsaturated compounds of sulfur, selenium and tellerium. A series of reactions of acetylene with sulfur, selenium and tellerium proceeding in DMSO or HMPA in the presence of alkali and water at 80–120° leading to divinyl sulfide, divinyl selenide and divinyl teluride in 25–80% yields have been found. Thiophen, di-1-(1,3-butadienyl) sulfide, 1-vinyl-2-thiabicyclo[3.2.0]hept-3-ene, and dihydrothiophen have been obtained by the reaction of vinylacetate with sulfur. The reaction of vinylacetylene with selenium affords selenophen, di-1-(1,3-butadienyl) selenide, 1-vinyl-2-selenabicyclo[3.2.0]hept-3-ene, methyl (1-(1,3-butadienyl) sulfide, and methylthiomethyl 1-(1,4-butadienyl) selenide, vinyl 1-(1,3-butadienyl) sulfide, and methylthiomethyl 1-(1,3-butadienyl) selenide (the latter two with DMSO participation). The reaction of vinylacetate with tellerium gives mainly di-1-(1,3-butadienyl) telluride. A series of reactions between DMSO and selenium leading to dimethyl sulfide, dimethyl sulfoselenide, and methylthiomethyl selenide have been observed.

Divinyl selenide: conformational study and stereochemical behavior of its 77Se1H spin–spin coupling constants

Theoretical energy‐based conformational analysis of divinyl selenide performed at the MP2/6‐311G** level is substantiated by the second‐order polarization propagator approach (SOPPA) calculations and experimental measurements of its 77Se1H spin–spin coupling constants, demonstrating marked stereochemical behavior in respect of the internal rotation of both vinyl groups around the SeC bonds. Based on these data, divinyl selenide is shown to exist in an equilibrium mixture of three nonplanar conformers: one the preferred syn‐s‐cis‐s‐trans and two minor anti‐s‐trans‐s‐trans and syn‐s‐trans‐s‐trans forms. Copyright

Synthesis of Novel E-2-Chlorovinyltellurium Compounds Based on the Stereospecific Anti-addition of Tellurium Tetrachloride to Acetylene

The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyl)tellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl3 under a pressure of acetylene of 10–15 atm, whereas the former product was formed in up to 72% yield in CCl4 under a pressure of acetylene of 1–3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl) telluride, E,E-bis(2-chlorovinyl) ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl)-tellurium dibromide is described.

Conformational analysis and diastereotopic assignments in the series of selenium-containing heterocycles by means of 77Se-1H spin-spin coupling constants: a combined theoretical and experimental study.

A combined theoretical and experimental study on the stereochemical behavior of 77Se‐1H spin‐spin coupling constants has been performed at the second‐order polarization propagator approach level together with heteronuclear multiple‐bond correlation technique in the series of selenium‐containing four‐, five‐ and six‐membered heterocycles including the derivatives of thiaselenetane, selenasilole, thiaselenole, thiaselenolane and dihydrothiaselenine. Geminal and vicinal 77Se‐1H spin‐spin couplings were shown to have the pronounced stereochemical dependences in respect with the topology of the coupling pathway, internal rotation of the side‐chain substituents and ring inversion providing a straightforward tool for the conformational analysis and diastereotopic assignments in the chiral organoselenium compounds. Copyright

SYNTHESIS OF VINYLIC SELENIDES AND TELLURIDES BY THE ADDITION OF ALKANESELENOLATE AND -TELLUROLATE ANIONS TO ACETYLENES

Abstract Alkaneselenolate and -tellurolate anions, which are generated from dialkyl dichalcogenides in the system potassium hydroxide-hydrazine hydrate-dimethyl sulfoxide-water, add to acetylene and phenylacetylene to give alkyl vinyl chalcogenides and (Z)-alkyl styryl chalcogenides in high yield.

Reactions of selenium and tellurium metals with phenylacetylene in three-phase catalytical systems

Abstract Compounds 2 , 6 a-d, 7 , 8 were prepared in three-phase catalytical systems using selenium and tellurium metals as one phase. A radical anion chain mechanism is proposed in the reaction of tellurium metal with phenylacetylene.

Reaction of selenium dibromide with divinyl sulfide

We found that the reaction of selenium dibromide with divinyl sulfide leads to an earlier unknown heterocyclic compound 5-bromo-2-bromomethyl-1,3thiaselenolane (I) in 80% yield. Selenium dibromide was prepared in situ by the reaction of selenium with bromine in chloroform. 5-Bromo-2-bromomethyl-1,3-thiaselenolane (I). Major diastereomer. Н NMR spectrum, δ, ppm: 3.79– 3.84 m (2Н, СН2Se), 3.86 m (1Н, СН2Br), 3.99 d. d (1Н, СН2Br, J 9.4, J 8.0 Hz), 5.03 t (1H, SСНSe, J 8.0 Hz), 6.10 d.d (1Н, SСНBr, J 3.3, J 3.4 Hz). С NMR spectrum, δ, ppm: 38.47 (CH2Br), 45.97 (CH2Se), 48.18 (SCHSe), 59.69 (SCHBr). Se NMR spectrum, δ, ppm: 410. Minor diastereomer. Н NMR spectrum, δ, ppm: 3.69–3.73 m (2Н, СН2Br), 3.70 m, 3.89 m (2Н, СН2Se), 5.05 t (1H, SСНSe, J 7.9 Hz), 5.91 d. d (1Н, SeСНBr, J 4.1, J 4.3 Hz). С NMR spectrum, δ, ppm: 37.50 (CH2Br), 44.39 (CH2Se), 47.27 (SCHSe), 58.36 (SCHBr). Se NMR, δ, ppm: 415. Found, %: С 15.00; Н 1.69; Br 49.38. C4H6Br2SSe. Calculated, %: С 14.79; Н 1.86; Br 49.18. The NMR spectra were taken on a Bruker DPX-400 instrument in CCl4 at working frequencies of 400.13 (Н, HMDS), 100.61 (С, HMDS), and 76.30 MHz (Se, Me2Se). ACKNOWLEDGMENTS

Alkylvinyl tellurides from tellurium, acetylene and alkyl halides

Abstract Synthetic routes to alkylvinyl tellurides by direct reaction of metallic tellurium, acetylene and alkyl halide in the system KOH-SnCl2-H2O and successive interaction of divinyl telluride with lithium and alkyl halide in liquid ammonia have been developed.