Free-radical addition of phenyl- and diphenylphosphines to 2-vinyl-1,3-dioxa-6-aza-2-silacyclooctanes

Conclusions Phenyl- and diphenylphosphines add to 2,6-dimethyl-2-vinyl-1,3-dioxa-6-aza-2-silacyclooctane upon the action of UV irradiation to form 2,6-dimethyl-2-[(2-phenylphosphino)ethyl)]-1,3-dioxa-6-aza-2-silacyclooctane and 2,6-dimethyl-2-[(2-diphenylphosphino)ethyl]-1,3-dioxa-6-aza-2-silacyclooctane, respectively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2615–2616, November, 1985.     

Synthesis of Dialkoxydimethylsilanes and 2,2-Dimethyl-1,3-dioxa- 1-Silacyclo Compounds

In the presence of iodine, magnesium reacts with alcohols to give magnesium alkoxides, which are treated with octamethylcyclotetrasiloxane to produce dialkoxydimethylsilanes. Similarly, magnesium reacts with 1,3, 1,4 and 1,5 diols and then with octamethylcyclotetrasiloxane, producing 2, 2-dimethyl-1, 3-dioxa-2-silacyclo compounds.     

8,10-Dimethyl-7,13-dioxa-10-azaspiro[5.7]tridecane — the first representative of perhydro-1,3-dioxa-6-azocines

The first representative of perhydro-1,3-dioxa-6-azocines, 8,10-dimethyl-7,13-dioxa-10-azaspiro[5.7]tridecane, was synthesized by the reaction of 4-methyl-1-oxa-4-azaspiro[4.5]decane with propylene oxide. The structure of the compound has been confirmed by IR and¹H and¹³C NMR spectroscopy and mass spectrometry.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1838–1839, September, 1995.     

Polymers of 2-vinyl-1,3-dioxolanes

Lewis acid-initiated polymerizations of 2-vinyl-1,3-dioxolanes have been studied. Evidence is presented showing at least three types of structural units in the polymer. Polymerization is propagated by 1,2 addition, by acetal ring opening, and by rearrangement, ring opening mechanisms. Polymerization is accompanied by the formation of a dimer consisting of a 1,4-dioxepane and 1,3-dioxolane ring. Film formers from methacrylate esters of vinyl dioxolane compounds are also described.     

Dimerization of a lattice-framework silanone into the corresponding 1,3-dioxa-2,4-disiletanes

A lattice-framework silanone, a racemate of (4R,6R)- and (4S,6S)-2,3,4,6,7,8-hexa-tert-butyl-1,5-disilatricyclo[4.2.0.0^1,4]octa-2,7-dien-5-one (4), was generated by the photoreaction of the corresponding lattice-framework disilene, a racemate of (4R,6R,4′R,6′R)- and (4S,6S,4′S,6′S)-2,3,4,6,7,8,2′,3′,4′,6′,7′,8′-dodeca-tert-butyl-[5,5′]bi{1,5-disilatricyclo[4.2.0.0^1,4]octylidene}-2,7,2′,7′-tetraene (dl-1), with mesitonitrile oxide. The silanone 4 was dimerized to produce a mixture of the corresponding dl- and meso-1,3-dioxa-2,4-disiletane derivatives 2. DFT calculations suggested that the non-selective dimerization of 4 to 2 is attributed to the irreversibility of the reaction.     

Homolytic addition of 2-ethoxy-1,3-dioxolane to 1-decene

Conclusions The radical addition of 2-ethoxy-1,3-dioxolane to 1-decene leads mainly to the formation of 2- and 4-decyl-2-ethoxy-1,3-dioxolane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2051–2053, September, 1985.     

Abinitio方法研究2，4－二甲基－1，3－戊二烯结构

用ａｂｉｎｉｔｉｏ方法研究２，４－二甲基－１，３－戊二烯各种构象异构体的结构，找到ｓ－ｔｒａｎｓ和ｓ－ｃｉｓ两种稳定构象，且ｓ－ｔｒａｎｓ更稳定．对稳定构象的几何结构、电荷分布进行了研究，讨论了不同的电子基组对优化几何的影响，并计算了稳定构象的热力学常数，与实验结果进行了比较．     

Cationic polymerization of 2-vinyl-1,3-dioxane

The cationic polymerization of 2-vinyl-1,3-dioxane initiated with triethyloxonium tetrafluoroborate was studied with particular emphasis on elucidation of the structure of the polymer. The polymer was a light yellow powdery material with a molecular weight of several thousands which was soluble in most organic solvents. The infrared and NMR investigations on the polymer, together with chemical analyses, showed that the polymer consisted of the three structural units I, II, and III, the contents of which were estimated to be 5–10%, 20–25%, and 65–70%, respectively. The formation of the structural units I and II was discussed in detail.     

Homolytic cyclization of 1,3-propanedithiol to 1,2-dithiolane in the presence of 2,5-dimethyl-2,4-hexadiene

2,2-Diethyl-1,3-propanedithiol undergoes cyclization to 4,4-diethyl-1,2-dithiolane upon interaction with 2,5-dimethyl-2,4-hexadiene in benzene in the presence of azodiisolbutyronitrile. The reaction proceeds according to the radical chain mechanism. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2078–2080, October, 1998.     

Synthesis and conformation of some 2,4-dioxa- and 2,4-dioxa-3-silabicyclo[3.3.1]nonanes

The conformation of the title compounds established by ¹³C and ¹H NMR spectroscopy shows that replacement of the 2- and 4-methylene groups in bicyclo[3.3.1]nonane by ether oxygen atoms strongly destablizes the cc conformation: in 2-oxabicyclo[3.3.1]-nonane the cc and the bc conformers are about equally populated, whereas in 2,4-dioxabicyclo[3.3.1]nonane the bc conformation predominates. The 2,4-dioxa-3-silabicyclo[3.3.1]nonanes also occur predominantly inthe bc conformation. As in the carbocyclic bicyclo[3.3.1]nonanes both wings are strongly flattened. A stereoselective synthesis of 3-methylbicyclo[3.3.1]nonane, an important model compound in this study, is described.     

Novel catalytic rearrangements of 2-vinyl-1,3-thiazetidines

The thiazetidines (1) and (2) undergo a novel and high yielding rearrangement on hydrogenation with heterogeneous catalysis to give the thiazolidines (5) and (8) whilst reaction with the homogeneous catalyst Rh(Ph₃P)₃Cl results in the alternative high yielding rearrangement to give a thiazine.     

1,3-Dioxa-2-silacyclohexane in nanotubes: Conformational transformations and structural features

Using the hybrid DFT method PBE/3ζ conformational transformations of 1,3-dioxa-2-silacyclohexane in the model one-layer carbon nanotubes were investigated. It was found that the effect of the nanotube force field results in shortening of the Si–O bond distances, decrease in the OSiO bond angle and increase in the interconversion barrier between the chair or semi-chair forms, as well as in appearing of the negative charge on the encapsulated molecule.     

Cationic copolymerization of 2-vinyl-1,3-dioxane with styrene and 1,3-dioxolane

Copolymerization of 2-vinyl-1,3-dioxane with styrene and 1,3-dioxolane was carried out in methylene chloride at 0°C with triethyloxonium tetrafluoroborate as an initiator. Random copolymers were obtained from both of these monomer pairs, but attempted copolymerization of 2-vinyl-1,3-dioxane with 3,3-bis(chloromethyl)oxetane under similar conditions resulted in the homopolymer of the latter monomer. There were three structural units of 2-vinyl-1,3-dioxane in these copolymers as in its homopolymer: the “ester” unit, which was formed by vinyl addition with hydride shift followed by ring-opening rearrangement, the “vinyl” unit produced by ring-opening reaction, and the unit with a pendant 1,3-dioxane ring formed by simple vinyl addition. The fractions of the ester and vinyl units to the total 2-vinyl-1,3-dioxane units in the copolymer of 2-vinyl-1,3-dioxane with styrene decreased with decreasing 2-vinyl-1,3-dioxane content. On the contrary, the fraction of the vinyl unit in the copolymer of 2-vinyl-1,3-dioxane with 1,3-dioxolane increased slightly with decreasing 2-vinyl-1,3-dioxane content, while that of the ester unit decreased. The reactivities of the propagating species are discussed on the basis of these results.     

Homolytic addition of 1,3-oxathiolane to unsaturated hydrocarbons

The homolytic addition of 1,3-oxathiolane to olefins takes place with the formation of 2-substituted 1,3-oxathiolanes and insignificant amounts of functional derivatives of sulfides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 259–263, February, 1986.     

FTIR Spectroscopic Studies on the Conformational Equilibrium of Liquid 2,4-Dimethyl-1,3-Pentadiene

Investigations of 2,4-dimethyl-1,3-pentadiene by variable temperature FTIR spectra have concluded that the compound is a mixture of two kinds of single bond isomer,i.e.,s-traiis and s-cis conformers.The changes of IR band intensities have been recorded at research temperature range.The values of △H° and △S° between two stable conformers have been deduced to be 4.37 kJ/mol and 2.48 J/mol K respectively.