Catalyst-free addition of secondary phosphine chalcogenides to pyrazolecarbaldehydes

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Radical addition of secondary phosphine chalcogenides to allylamine: Atom-economic synthesis of aminopropylphosphine chalcogenides

Secondary phosphine sulfides and phosphine selenides react with allylamine under the conditions of radical initiation (UV or AIBN) to form the anti-Markovnikov adducts in up to 93 % yield.     

Reaction of secondary phosphine chalcogenides with diallylamine

Diphenyl- or bis(2-phenylethyl)phosphine sulfides and -phosphine selenides react with diallylamine under radical initiation (UV or AIBN) to afford the corresponding diadducts and tetrahydropyrrolylmethyl phosphine chalcogenides. The yield and the ratio of the products depend on the structure of the starting secondary phosphine chalcogenides.     

Reaction of secondary phosphine chalcogenides with 2,2,2-trichloroacetaldehyde

The nucleophilic addition of secondary phosphine chalcogenides to 2,2,2-trichloroacetaldehyde proceeds under mild noncatalytic conditions (12–25dgC, 15–90 min) with the formation of functional tertiary phosphine chalcogenides, containing hydroxy groups in up to 98% yield. Using the method of concurrent reactions the reactivity of secondary phosphine chalcogenides in this reaction was shown to decrease in the order: (PhCH₂CH₂)₂P(O)H ≫ (PhCH₂CH₂)₂P(S)H > (PhCH₂CH₂)₂P(Se)H, and the secondary bis[2-(2-pyridyl) ethyl]-phosphine oxide was more reactive than bis(2-phenethyl)phosphine oxide.     

Reaction of divinyl selenide with secondary phosphine chalcogenides

Under the conditions of free-radical initiation (AIBN, UV irradiation), divinyl selenide regioselectively reacts with secondary phosphine sulfides and phosphine selenides to afford, depending on the ratio of the reagents, mono- or diadducts mainly of the anti-Markownikoff structure. The conditions which allow obtaining the diadducts in up to 97% yield are found. By the example of 2-{[2-(diphenethylphosphoroselenoyl) ethyl]selanyl}ethyl(diphenethyl)phosphine selenide the diadducts were shown to react with aqueous hydrogen peroxide at 53–56°C to give vinyl(diphenethyl)phosphine oxide in 76% yield.     

Reaction of divinyl telluride with secondary phosphine chalcogenides

Divinyl telluride reacted with 2 equiv of diphenylphosphine sulfide in the presence of AIBN as radical initiator (63–68°C) to give the corresponding anti-Markovnikov adduct in 68% yield with high regioselectivity. Treatment of the addition product with aqueous hydrogen peroxide at room temperature afforded 71% of vinyldiphenylphosphine oxide. Radical addition of diphenylphosphine selenide to divinyl telluride (AIBN, 63–68°C) led to the formation of 1,1,3,3-tetraphenyldiphosphoxane 1,3-diselenide in 82% yield.     

Stereoselective free-radical addition of secondary phosphine selenides to aromatic acetylenes

Free-radical addition (AIBN, 65-70 °C, 5-7 h) of secondary phosphine selenides to arylacetylenes proceeds stereoselectively to give anti-Markovnikov adducts of predominantly Z-configuration (up to 97%) in 60-80% isolated yields, thus representing a rare example of stereoselective free-radical addition to the triple bond. Microwave irradiation (600 W) of the reactants with the same content of AIBN reduces the reaction time to 8 min though compromises the stereoselectivity. Under UV-initiation the reaction loses its stereoselectivity due to isomerization of the primary Z-adducts. In this reaction, a specific facilitating and Z-configuration-controlling effect of aromatic substituents at the triple bond has been revealed.     

Atom-sparing synthesis of tertiary diphosphine dichalcogenides from acetylenes and secondary phosphine chalcogenides

Secondary phosphine oxides and phosphine sulfides react with acetylene, methylacetylene, and phenylacetylene in the presence of strong bases (KOH-DMSO, KOH-THF) by the mechanism of double nucleophilic α,β-addition to form tertiary diphosphine dioxides and diphosphine disulfides in high yield (up to 97%).     

Michael-type addition of secondary phosphine oxides to (1,4-cyclohexadien-3-yl)phosphine oxides

Base-induced reaction between (1,4-cyclohexadien-3-yl)phosphine oxides and secondary phosphine oxides gives 3,4-bis(phosphinoyl)cyclohexenes and 2,3-bis(phosphinoyl)cyclohexenes through an in situ isomerization of one of the cyclohexadienyl double bonds and a subsequent Michael-type addition of the secondary phosphine oxide.     

Radical addition of secondary phosphine sulfides and selenides to vinyl tellurides

The regiospecific addition of secondary phosphine sulfide and phosphine selenide to alkyl vinyl tellurides proceeds under radical initiation (AIBN, 65–70 °C, 2.5–3.5 h) to afford the anti-Markovnikov adducts, (2-alkyltellanylethyl)phosphine chalcogenides, in 86–99% yields.     

Catalyst-free regio- and chemoselective addition of secondary phosphine oxides to isoquinolines

Russian Chemical Bulletin - Isoquinolines react with secondary phosphine oxides without catalyst (70–75 °C, 10–15 h, without solvent or in MeCN) to chemo- and regioselectively form...     

Air-induced anti-Markovnikov addition of secondary phosphine oxides and H-phosphinates to alkenes

[reaction: see text] Air (oxygen) induces the addition of secondary phosphine oxides and H-phosphinates to alkenes to selectively produce the corresponding anti-Markovnikov adducts in good to high yields. Mechanistic studies show that the addition probably proceeds via a radical chain mechanism.     

Chlorination of secondary phosphine chalcogenides with carbon tetrachloride in the absence of bases

The interaction of bis(2-phenylethyl)phosphine sulfide, bis(2-phenylethyl)phosphine selenide and bis[2-(2-phenyl)propyl]phosphine selenide with carbon tetrachloride under heating (80°C, 8–20 h) leads to the formation of the corresponding chlorophosphine chalcogenides with the yield of 80–90%.

     

Nucleophilic addition of secondary phosphine sulfides to divinyl sulfoxide and divinyl sulfone

Secondary phosphine sulfides readily undergo addition to divinyl sulfoxide and divinyl sulfone in the presence of KOH (THF, 20–22°C, 1 h) with regiospecific formation of bis[2-(diorganylthiophosphoryl)-ethyl] sulfoxides and sulfones. A dramatic increase in the electrophilicity of the double bond in the monoadduct suggests transfer of the electron-acceptor effect of the thiophosphoryl group directly though space, due to its donor-acceptor interaction with the polarized S-O bond. It was demonstrated by the example of divinyl sulfoxide that, when performed with equimolar amounts of reactants and a weaker base (LiOH), the reaction can be stopped at the stage of formation of the monoadduct.     

Chemoselective addition of organometallics to oxime ethers

In this paper, an efficient method for preparation of various substituted hydroxylamines from aldehydes is reported. We first prepare O-trimethylsilyl oxime ether in 5 M solution of lithiumperchlorate in diethyl ether (LPDE 5M) from condensation reaction between aldehyde and O-trimethylsilyl hydroxylamine, then add organosilane or organotin nucleophile in the same vessel to preparing the corresponding α-substituted hydroxylamines in one-pot synthesis.     

Oxidative coupling of hydroxy- or aminoazobenzenes with secondary phosphine chalcogenides: Towards new media-responsive molecular switches

One or two chalcogenophosphinate groups were introduced to the azobenzene scaffold via the oxidative cross-coupling reaction of 4-amino-, 4-hydroxy- and 4,4′-dihydroxyazobenzenes with secondary phosphine chalcogenides using the CCl₄/Et₃N system under mild conditions in 41–95% yield. Cis-trans photoisomerization of the phosphorylated azobenzenes was reversibly controlled by alternating UV/Vis light irradiation. The chalcogenophosphinate group imparts the properties of media-responsive molecular photoswitches to the synthesized azobenzenes.