Benzyl Phenyl Selenide Research Articles

An indium–TMSCl promoted reaction of diphenyl diselenide and diorganyl disulfides with aldehydes: novel routes to selenoacetals, thioacetals and alkyl phenyl selenides

The reactions of diphenyl diselenide and dialkyl disulfides with aldehydes in the presence of In–TMSCl have been investigated. Aliphatic aldehydes provide the corresponding selenoacetals and aromatic aldehydes lead predominantly to benzyl phenyl selenides on reaction with diphenyl diselenide. However, the reaction of dimethyl disulfide and diphenyl disulfide with both aromatic and aliphatic aldehydes produce dithioacetals. This provides a novel route to the synthesis of selenoacetals, thioacetals and selenides from aldehydes.

Highly Enantioselective Reaction of α-Selenoorganolithium Compounds with Chiral Bis(oxazoline)s and Preparation of Enantioenriched Benzylidencyclohexanes

The enantioselective reaction of alpha-seleno carbanions derived from bis(phenylseleno)acetal and bis(2-pyridylseleno)acetal in the presence of bis(oxazoline)s with various electrophiles gave products with high enantioselectivity. The enantioselective reaction of alpha-lithio benzyl 2-pyridyl selenide gave the products with stereochemistry reverse to that obtained in the reaction of alpha-lithio benzyl phenyl selenide. Mechanistic investigation suggests the enantiodetermination of these reactions at -78 degrees C depends on dynamic thermodynamic resolution. The enantioselective reaction was applied to the preparation of enantioenriched olefins and epoxide.

Persistent radical effect in the intramolecular addition of benzylic radicals onto ketenimines: selective cross-coupling of α-(indol-2-yl)benzyl radicals with the 1-cyano-1-methylethyl radical

The intramolecular addition of benzylic radicals, generated from benzyl phenyl selenides by the action of tris(trimethylsilyl)silane and AIBN or AIBMe, onto neighbouring ketenimine functions is studied. The persistent α-(indol-2-yl)benzyl radicals, resulting from such cyclization processes, undergo cross-coupling with the tert-alkyl radicals arising from the thermal decomposition of the AIBN or AIBMe initiators to give, respectively, 3-(1H-indol-2-yl)propiononitriles 10 or propanoates 14. A rare spiropentacyclic compound 17 containing two indole fragments also resulted from one of these radical reactions. The crystal and molecular structures of 10d and 17 have been solved by X-ray analysis.

SYNTHESIS OF DIBLOCK COPOLYMERS BY END FUNCTIONAL POLYSTYRENE CONTAINING PHENYLSELENO GROUPS AS POLYMERIC PHOTOINIFERTER

ABSTRACT Block copolymers of styrene and p-substituted styrene were prepared by photopolymerization of p-bromostyrene or p-methylstyrene in the presence of end functional polystyrene (DPDSE-PST) containing phenyl-seleno groups at the α and ω-chain ends as polymeric photoiniferter. To determine the form of resulting block copolymers, the behavior of chain terminals of DPDSE-PST was investigated. The ability of photoinitiate and chain transfer of β-phenylethyl p-tert-butylphenyl selenide as a model compound of α-chain end of DPDSE-PST was much smaller than that of benzyl phenyl selenide as a model compound of ω-chain end of DPDSE-PST. On the other hand, the polymerization of styrene, prepared by 1,4-Bis(p-tert-butylphenyl) diselenide as photoiniferter, with styrene also revealed a form of the resulting block copolymer was an AB block structure.

Self-Assembled Monolayers of Organoselenium Compounds on Gold: Surface-Enhanced Raman Scattering Study

To understand the binding nature of organoselenium compounds on gold, we have examined the adsorption behavior of several representative organoselenium compounds, i.e., benzeneselenol (BSe), diphenyl diselenide, dibenzyl diselenide, dioctyl diselenide, and benzyl phenyl selenide (BPSe) on the Au surface by virtue of surface-enhanced Raman spectroscopy (SERS). BSe chemisorbs on gold as selenolate with a tilted orientation. Upon adsorption, the Se–Se bonds of diselenides are cleaved to form selenolates, analogous to the formation of thiolate monolayers from disulfides. BPSe adsorbs on gold without any C–Se bond scission. The benzyl moiety of BPSe assumes a rather vertical stance while the phenyl moiety is more tilted to the gold surface.

Radical Polymerization of p-Substituted Styrenes with Benzyl Phenyl Selenide as Photoiniferter

Benzyl phenyl selenides were used as photoiniferters for polymerizations of p-bromostyrene, p-chloromethylstyrene, p-methylstyrene, and p-vinylbenzyl acetate. In the limited range of conversion (≤50%), polymer yields and number-average molecular weights increased with polymerization time. Polymers from p-methoxybenzyl p-trimethylsilylphenyl selenide contained the benzyl and arylseleno groups at α- and ω-chain ends, respectively. Photoirradiation of polystyrene containing a phenylseleno group at the ω-chain end as polymeric photoiniferter afforded effectively block copolymers of styrene and p-substituted styrenes.

Organoselenide as a Novel Ionophore for a Silver-Selective Membrane Electrode

Three selenium-containing compounds, diphenyl selenide, benzyl phenyl selenide and dibenzyl selenide were used as neutral carriers to make a Ag+-selective membrane electrode. All three compounds exhibited higher sensitivity to Ag+ than the corresponding sulfides and ethers. The highest sensitivity was obtained by dibenzyl selenide and an electrode constructed using this carrier and bis(l-butylpentyl) adipate as a membrane solvent in a poly(vinyl chloride) membrane matrix exhibited a near-Nernstian response to Ag+ in the concentration range from 1 x 10−5 to 1 x 10−2 M with a slope of 52 mV per concentration decade. The lower limit of detection was around 1 μM. The ion selectivity of this electrode for Ag+ was over 104 times that for other metal cations. Dibenzyl selenide and Ag+ interactions were examined by 1H-NMR spectroscopy.

Synthesis of Polystyrene and Poly(methyl methacrylate) Each with a Phenyl Seleno Group at Terminal Chain End by Radical Polymerization in the Presence of Benzyl Phenyl Selenide as a Photoiniferter

The photopolymerization of styrene with benzyl phenyl selenide proceeded smoothly to give polystyrene having benzyl and phenylseleno groups at α- and ω-chain ends, respectively, and the degree of functionality was 0.95. In a limited range of conversion, both the polymer yields and number average of molecular weights (M̄n) increased with the reaction time and the M̄n linearly increased with yield. The addition of styrene to the polystyrene with irradiation increased the molecular weight of the polymer. In the photopolymerization of methyl methacrylate, similar polymerization behavior was observed. The tacticity of the poly(methyl methacrylate) was in good agreement with that prepared by radical mechanism. Photoirradiation of polystyrene having phenylseleno group at the ω-end in the presence of methyl methacrylate effectively afforded a block copolymer of styrene and methyl methacrylate.

Generation of metal phosphinites by the reaction of Se‐alkyl phosphinoselenoates with organometallics and its application to the synthesis of optically active organophosphorus compounds

AbstractReaction of Se‐Alkyl phosphinoselenoates with organometallics resulted in a selective attack on the selenium atom. Sequential treatment of optically active Se‐benzyl t‐butylphenylphosphinoselenoate with PhLi and then with electrophiles, such as alkyl halides, an α,β‐unsaturated ester, and chalcogen atoms gave optically active phosphorus compounds in 5–91% yields and in high optical yields, with retention of configuration at the phosphorus atom, along with a quantitative yield of benzyl phenyl selenide.

Electrochemical behaviour of pharmcologically interesting selenoorganic compounds. Part 4-ortho-benzylseneno benzanilide

The electrochemical behaviour of 2-(benzylseleno)benzanilide was investigated by voltammetry using a rotating platinum electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. The measurements were made in acetonitrile medium. Comparison in terms of potential values and obtained products were made between 2-(benzylseleno)benzanilide, benzyl phenyl selenide and their sulphur analogues.

Electrochemical behaviour of selenoorganic compounds—part 4. benzyl phenyl selenide

The electrochemical behaviour of benzyl phenyl selenide was investigated by voltammetry using a rotating platinum disk electrode, cyclic voltammetry, controlled potential coulometry and electrolysis. The measurements were made in acetonitrile solution. In contrast to the case of benzyl phenyl sulfide, the oxidation products diphenyl diselenide, benzaldehyde and N-benzylacetamide result from the evolution of benzyl phenyl selenoxide and not from the corresponding initially formed radical cation

Synthesis of Optically Active Phosphorus Compounds via Metal Phosphinites Generated by Reaction of Optically Active Selenophosphinates with Phenyllithium

Abstract Sequential treatment of optically active Se-benzyl t-butylphenylselenophosphinate with PhLi and then with electrophiles such as alkyl halides and elemental selenium gave optically active phosphorus compounds in good chemical and optical yields with a retention of configuration at phosphorus atom, together with benzyl phenyl selenide.

Samarium (II) diiodide‐induced reductive cleavage of SeSe and TeTe bond in diphenyl diselenide and ditelluride leading to a samarium phenylselenolate and tellurolate: Preparation of unsymmetrical alkylphenyl selenides and tellurides

AbstractDiphenyl diselenide and diphenyl ditelluride were reduced by samarium (II) diiodide in tetrahydrofuran‐hexamethylphosphoric triamide to produce samarium phenylselenolate and samarium phenyltellurolate, respectively. This new selenolate or tellurolate anion species reacted smoothly with alkyl, allyl, and benzyl halides to give alkyl‐, allyl‐, and benzylphenyl selenides or tellurides in good yields under mild and neutral conditions. The samarium selenolate reacted with α‐halo ketones to give the corresponding α‐phenylseleno ketones. 1,4‐Addition with α,β‐enones proceeded to give 3‐phenylseleno ketones in moderate yields. Isolation of phenylselenotributyltin or phenylseleno‐trimethylsilane by transmetalation with tributyltin iodide or trimethylchlorosilane, respectively, suggested the presence of the samarium selenolate species.

ChemInform Abstract: Selenylation of cis‐ and trans‐1,2‐Dichloroethenes and Vinylidene Chloride Under Phase‐Transfer Catalysis Conditions.

AbstractThe reactions between cis‐dichloroethene (I), its trans isomer (VII) or a mixture of these and phenylselenol (II) under the conditions of phase‐transfer catalysis afford the cis‐1‐phenylseleno‐2‐chloroethene (III) as the main product along with its trans isomer (IV), 1‐phenylseleno‐1‐chloroethene (V) and benzyl phenyl selenide (VI).

NEW SYNTHETIC METHOD OF [2.2]PARACYCLOPHANE, BENZOCYCLOBUTENE, AND LEPIDOPTERENE: PYROLYSIS OF ARYLMETHYL PHENYL SELENIDES

Abstract The flash vacuum pyrolysis of benzyl phenyl selenides gave bibenzyls and diphenyl diselenide in excellent yields. This type of reaction was successfully applied to the synthesis of the title compounds.

Thermal and photochemical reactions of organocobaloximes with diphenyl disulphide and diphenyl diselenide

Alkyl- and benzyl-bis(dimethylglyoximato)pyridinecobalt(III) complexes react with diphenyl disulphide or diphenyl diselenide, thermally and photochemically, to give good yields of alkyl or benzyl phenyl sulphides or selenides. Chiral alkylcobalt(III) complexes react to give racemic alkyl phenyl sulphides or selenides. Allyl- and propadienyl-bis(dimethylglyoximato)pyridinecobalt(III) complexes react similarly to give the thermodynamically more stable allyl, propadienyl, or propynyl phenyl sulphides or selenides. These reactions are interpreted in terms of free radical processes in which organic radicals formed as a result of thermal, photochemical, or chemically induced homolysis of the organocobalt complex, attack the diphenyl dichalcogenide to give the product organo phenyl chalcogenide. No evidence could be obtained for the direct attack of phenylthyl or phenylselenyl radicals on the organic ligand of the organocobalt complexes, though this process cannot be exluded in the case of allyl-cobalt complexes.

The synthesis and reactions of 2,11-diselena[3,3]metacyclophanes. An investigation of the selenoxide elimination route to metacyclophane-1,8-dienes

2,11-Diselena[3,3]metacyclophane and its 9,18-dimethyl derivative are prepared in ca. 7% yield from Na2Se and xylylene bromide. Wittig rearrangement and benzyne induced Stevens rearrangement gave the ring contracted [2,2]metacyclophane derivative. Attempted selenoxide elimination to produce metacyclophane-diene failed. The 1Hmr spectra of the selenametacyclophane indicate that the syn-conformer is the more stable. A general synthesis of aryl-alkenes in an 80% yield starting from benzyl phenyl selenide, alkylation with an alkyl halide, and then selenoxide elimination is given.

Photorearrangement of phenyl selenide derivatives. Access to selenium substituted C-nucleosides

The photorearrangements of benzyl phenyl selenide and phenyl ribosyl selenide derivatives afford 2-benzyl phenylselenol and 2-ribosyl phenylselenol, respectively which can be isolated as their methyl derivatives.

ChemInform Abstract: SIMPLE SYNTHESIS OF TRANS‐ALKENES FROM HALIDES BY SELENOXIDE FRAGMENTATION

AbstractDie Alkylbromide (I) reagieren mit Natriumselenophenolat (II) zu den Seleniden (III), deren Anionen (IV) mit den Alkylbromiden (V) zu den Seleniden (VI) alkyliert werden.

Simple synthesis of trans-alkenes from halides by selenoxide fragmentation

Alkylation of benzyl phenyl selenides (prepared from benzyl halides) with alkyl or arylalkyl halides followed by oxidation to the selenoxide and elimination results in ca. 80% yields of trans-alkenes.