Reaction of dialkyl(or aryl) dichlorosilanes with alkali metals in presence of conjugated dienes

Summary The reaction of dialkyl(or aryl)dichlorosilanes with conjugated dienes in presence of alkali metals in a tetrahydrofuran medium leads to the formation of unsaturated sila-hydrocarbon polymers with silicon atoms in the main chain and molecular weights of 1000 or over, and also the corresponding silacyclopentenes (yields 0–10%) and divinylsilacyclopentanes (yields 10–50%). The relative amounts (yields) of these products depend both on the nature of the reactants and on the reaction conditions.Translated from Izvestiya Akademii Nauk SSR, Seriya Khimicheskaya, No. 5, pp. 840–844, May, 1964     

Electrochemical reduction of aliphatic conjugated dienes in the presence of carbon dioxide

A voltammetric and electrolytic study involved in the electroreductive carboxylation of multi-substituted aliphatic coujugated dienes has been successfully conducted. With methyl sorbate as the modal compound, acceptable yields of carboxylation and dimerization were achieved, which were influenced by various reaction conditions such as the supporting electrolyte, cathode nature, current density, charge passed and temperature. A correlation was first established between distinct electronic effects of the dienes and the electrochemical characteristics of their reduction and the distribution law of target products.     

Cu(I)-catalyzed asymmetric diamination of conjugated dienes

A Cu(I)-catalyzed asymmetric diamination for a variety of conjugated dienes and a triene with encouraging ee's has been effectively achieved using (R)-DTBM-SEGPHOS as a chiral ligand and di- tert-butyldiaziridinone as the nitrogen source.     

Diamination of conjugated dienes and trienes catalyzed by N-heterocyclic carbene-pd(0) complexes

This paper describes a diamination process using di-t-butyldiaziridinone as nitrogen source and N-heterocyclic carbene-Pd(0) complex as catalyst. A wide variety of conjugated dienes and trienes can be effectively diaminated in good yields with high regio- and stereoselectivities.     

Pd(II)-catalyzed intermolecular 1,2-diamination of conjugated dienes

A Pd(II) chloride precatalyst, in the presence of 1 equiv of benzoquinone, effects highly efficient, regioselective 1,2-diamination of 1,3-dienes using dialkyl ureas under mild conditions. There is no requirement for a large excess of diene.     

Arylsulfenylation of heterocyclic compounds with arylsulfenamides in the presence of phosphorus(V) oxochloride

The electrophilic sulfenylation of a series of indoles and pyrroles with arylsulfenamides in the presence of phophorus(V) oxohalide has been studied. It has been shown that arylsulfenylation of indoles led to products with substitution at position 3, while in the case of pyrrole it occurred at position 2.     

Diacetoxylation of conjugated dienes with thallium(III) acetate in acetic acid

The reaction of conjugated dienes such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2,5-dimethyl-2,4-hexadiene, 1,3-cyclopentadiene, and 1,3-cyclohexadiene, with thallium(III)acetate in acetic acid at 10–65° for 0.5–15 hr affords an isomeric mixture of the corresponding diacetoxyalkenes (1,2- and 1,4-addition products) in 10–92% yields. The 1,2-addition products are predominantly formed in all cases examined except the case of 1,3-cyclopentadiene. The reaction is assumed to proceed through acetoxythallation and dethallation steps, the latter step being accompanied and/or followed by an attack of acetoxyl group. An initial attack of thallium moiety is proposed to occur mainly at C-1 and C-2 carbons in the cases of linear terminal dienes and cyclic dienes, respectively.     

Selective 1,4-diacetoxylation of conjugated dienes with tellurium (IV) oxide

Oxidation of several linear conjugated dienes with tellurium (IV) oxide and lithium bromide in acetic acid affords an isomeric mixture of the corresponding diacetoxyalkenes (1,2- and 1,4-addition products), 1,4-isomer being highly selectively produced when the ratio of LiBr/TeO₂, is 5–10.     

A mild Cu(I)-catalyzed regioselective diamination of conjugated dienes

This paper describes a novel diamination process that uses CuCl as catalyst and di-tert-butyldiaziridinone as nitrogen source. A wide variety of conjugated dienes and a triene can be effectively diaminated in good yields with generally high regioselectivity under mild reaction conditions.     

β-Aminoselenenation of alkenes with arylselenenamides in the presence of sulfamic acid

Russian Chemical Bulletin -     

Preparative procedure of dihalosulfenylation: Thiobisamines addition to unsaturated compounds in the presence of phosphorus oxyhalides and halides

A new synthetic method was developed for \,\′-dihaloalkyl sulfides (halogen chlorine or bromine) by reaction of thiobisamines with olefins and alkynes in the presence of the appropriate phosphorus halides. The reaction proceeds along electrophilic mechanism affordingtrans-addition products. The highest yields of the target products were obtained at POBr₃ or POC1₃ application. The study was carried out under financial support of the Russian Foundation for Basic Research (grant no. 99-03-33093).     

Hydroamination of conjugated dienes catalyzed by transition metal complexes

The review summarizes published data on the hydroamination of 1,3-dienes with various primary and secondary amines, ammonia, and ammonium salts of mineral acids in the presence of transition metal complexes under homogeneous conditions. The effects of the nature of metal, ligand, initial diene, and amine and reaction conditions on the selectivity of hydroamination are considered, and possible reaction mechanisms are discussed.     

Ditolyldithiophosphato derivatives of phosphorus(III) and phosphorus(V)

O,O′-Ditolylphosphorodithioates of phosphorus(III), [(o-, m-, or p-CH₃C₆H₄O)₂PS₂] _n PCl_3−n , and phosphorus(V), [(o-, m-, or p-CH₃C₆H₄O)₂-PS₂] _n POCl_3−n , (n = 1, 2, and 3) were isolated as colorless viscous liquids by the reaction of PCl₃ and POCl₃ with sodium ditolylphosphorodithioate, (o-, m-, or p-CH₃C₆H₄O)₂PS₂Na, in 1:1, 1:2, and 1:3 molar ratios in toluene. These compounds were characterized by elemental analyses, molecular weight measurements, IR, and NMR (¹H, ³¹P, and ¹³C) spectroscopic studies, which indicated a less common monodentate linkage of dithiophosphate moieties in both phosphorus(III) and phosphorus(V) derivatives leading to a tetrahedral geometry around the phosphorus atom. Correspondence: Sushil K. Pandey, Department of Chemistry, University of Jammu, Baba Saheb Ambedkar Road, Jammu 180 006 (J & K), India.     

Ditolyldithiophosphato derivatives of phosphorus(III) and phosphorus(V)

O,O′-Ditolylphosphorodithioates of phosphorus(III), [(o-, m-, or p-CH₃C₆H₄O)₂PS₂] _n PCl_3−n , and phosphorus(V), [(o-, m-, or p-CH₃C₆H₄O)₂-PS₂] _n POCl_3−n , (n = 1, 2, and 3) were isolated as colorless viscous liquids by the reaction of PCl₃ and POCl₃ with sodium ditolylphosphorodithioate, (o-, m-, or p-CH₃C₆H₄O)₂PS₂Na, in 1:1, 1:2, and 1:3 molar ratios in toluene. These compounds were characterized by elemental analyses, molecular weight measurements, IR, and NMR (¹H, ³¹P, and ¹³C) spectroscopic studies, which indicated a less common monodentate linkage of dithiophosphate moieties in both phosphorus(III) and phosphorus(V) derivatives leading to a tetrahedral geometry around the phosphorus atom.     

Sensitized photo-oxygenation of acyclic conjugated dienes

Sensitized photo-oxygenation of a wide variety of acyclic 1,3-dienes was investigated. The 1,4-cycloaddition of singlet oxygen to acyclic conjugated dienes was closely related to the thermal Diels-Alder reaction in stereospecificity, and steric and electronic effects of substituents. Reactivity order of singlet oxygen toward conjugated dienes and isolated C—C double bonds was exhibited as follows: trisubstituted mono-olefins > 2-substituted 1,3-dienes > disubstituted mono-olefins.     

On the valence excited states of conjugated dienes

Electron impact spectroscopic results are reported for the lowest-energy A_g and B_u valence excited states of several conjugated dienes. In all cases, the B_u state was found to lie below the A_g state. The B_u state of the s-cis compounds was found to be ≈ 0.5 eV lower in energy than that of the s-trans compounds. Correlations of these results with those obtained for several s-trans and s-cis polyenes leads to a new possible interpretation of the state observed below the B_u state in intermediate length polynes.