- Stereoselective Catalytic Synthesis of Alkynylated Phosphaethenes Leading to Activation-Free Gold Catalysis
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The π-accepting property of alkene-like phosphaethenes (–P=Ca sterically encumbered gem-dibromophosphaethene by a Sonogashira process has been accomplished, and the corresponding 2-alkynyl-2-bromo-1-phosphaethenes were obtained. Subsequent arylation of the 2-alkynyl-2-bromo-1-phosphaethenes by the palladium version of the Kumada–Tamao–Corriu (KTC) reaction gave the corresponding 2-alkynyl-2-aryl-1-phosphaethenes through an inversion of the configuration. The 2-alkynyl-2-aryl-1-phosphaethenes were converted into the corresponding chloro-gold(I) complexes, and screening of their catalytic activity revealed that both appropriate π-conjugative substituents and the stereochemistry were decisive for the efficiency of the gold-catalyzed reactions under activation-free conditions. Chloro-gold complexes bearing 2,2-diaryl-1-phosphaethene ligands showed moderate-to-good catalytic activity.
- Ito, Shigekazu,Shinozaki, Tomokazu,Mikami, Koichi
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- Synthesis of a 1,3-diphosphacyclobutane-2,4-diyl from Mes*C≡P
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A very stable biradical, 2, was prepared from 1 (see picture). The deep-blue/violet biradical was stable in the air for several minutes. The sp2-hybridized carbon radical centers of 2 were confirmed by X-ray crystallography and its reversible o
- Sugiyama, Hiroki,Ito, Shigekazu,Yoshifuji, Masaaki
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- Reaction of the Phospha-alkyne ArCP (Ar = 2,4,6-But3C6H2) with Nucleophiles: A New Approach to 1,3-Diphosphabutadiene Synthesis
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The reactions of ArCP (Ar = 2,4,6-But3C6H2) with the nucleophiles MeLi and Li are described; the X-ray crystal structure of ArCP is also reported.
- Arif, Atta M.,Barron, Andrew R.,Cowley, Alan H.,Hall, Stephen W.
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- A new synthesis of 1-phosphaalkyne via phosphaalkene with palladium(O) complex
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Reactions of the readily available phosphaalkene ArP = CCl2 (1; Ar = 2,4,6-t-Bu3C6H2) with tetrakis(triphenylphosphine)palladium(O) affords the phosphaalkyne Ar-C = P (3) in almost quantitative yield. The observ
- Romanenko,Sanchez,Sarina,Mazieres,Wolf
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- Photochemical C(sp)-C(sp2) Bond Activation in Phosphaalkynes: A New Route to Reactive Terminal Cyaphido Complexes LnM-CP
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The photochemical activation of the C(sp)-C(sp2) bond in Pt(0)-ν2-aryl-phosphaalkyne complexes leads selectively to coordination compounds of the type LnPt(aryl)(CP). The oxidative addition reaction is a novel, clean, and atom-economic route for the synthesis of reactive terminal Pt(II)-cyaphido complexes, which can undergo [3 + 2] cycloaddition reactions with organic azides, yielding the corresponding Pt(II)-triazaphospholato complexes. The C-C bond cleavage reaction is thermodynamically uphill. Upon heating, the reverse and quantitative reductive elimination toward the Pt(0)-phosphaalkyne-π-complex is observed.
- Boback, Nico,Coles, Nathan T.,Dittrich, Birger,Frost, Daniel S.,G?rlich, Tim,Jones, William D.,Müller, Christian,Müller, Peter
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supporting information
p. 19365 - 19373
(2021/11/26)
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- Dual supermesityl stabilization: A room-temperature-stable 1,2,4-triphosphole radical, sigmatropic hydrogen rearrangements, and tetraphospholide anion
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Cesium 3,5-bis(2,4,6-tri-tert-butylphenyl)-1,2,4-triphospholide (12) and cesium 5-(2,4,6-tri-tert-butylphenyl)tetraphospholide (13) were synthesized and isolated with flat fivemembered rings, which are an indication of the aromaticity in these anions. Compound 13 is the first example of a stable tetraphospholide anion, which is structurally characterized. Kinetic stabilization of the 1,2,4-triphospholide system by two supermesityl groups resulted in the detection of the room-temperature-stable radical 17 and the observation of a series of successive sigmatropic hydrogen shifts in the first stable 1H-1,2,4-triphosphole 14 with a P-H bond. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Ionkin, Alex S.,Marshall, William J.,Fish, Brian M.,Marchione, Alexander A.,Howe, Laurie A.,Davidson, Fredric,McEwen, Charles N.
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scheme or table
p. 2386 - 2390
(2009/03/11)
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- ArP=C=Si(Ph)Tip: The first allenic compound with doubly bonded phosphorus and silicon
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The first allenic compound with doubly bonded silicon and phosphorus, the 3-phospha-1-silaallene 1, has been obtained by dechlorination of the corresponding (chlorosilyl)chlorophosphaalkene 10 with tert-butyllithium at low temperature. Compound 1 was char
- Rigon, Leslie,Ranaivonjatovo, Henri,Escudie, Jean,Dubourg, Antoine,Declercq, Jean-Paul
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p. 774 - 781
(2007/10/03)
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- Palladium( 0) mediated coupling of bromophosphaalkenes with Grignard reagents
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Attempts to subject the phosphaalkene Mes * P = CBr2 (1) (Mes * = supermesityl = 2,4,6-tri-tert-butylphenyl) to a palladium(0) catalyzed Stille-type coupling reaction with phenylmagnesium chloride failed due to elimination of palladium bromide and rearrangement to the phosphaacetylene Mes * C≡P (2). To prevent this undesired reaction, the monobromophosphaalkene Mes * P=C(H)Br (6) was used. Although both isomers are known, a new method for the synthesis of (E)-Mes * P=C(H)Br ((E)-6) has been developed and the compound tested in Stille-type coupling reactions with organometallic reagents. Best results were obtained in combination with Grignard reagents; aromatic, olefinic and alkynyl groups could be introduced. Most unexpected was the result when (Z)-Mes * P=C(Br)H ((Z)-6) was subjected to this coupling reaction: in all cases, isomerization occurred to give (E)-Mes * P=C(H)R (7-17) in high yield and purity. This method offers a convenient access to a variety of new functionalized phosphaalkenes with potentially interesting coordinating properties. The mechanism of the coupling reaction appears not to involve the usual oxidative addition step, assumed to occur in the normal Stille coupling. Attempts to elucidate the mechanism are reported and the η2-palladium complex 19 has been tentatively identified as an intermediate.
- Van Der Sluis, Marcel,Klootwijk, Angelique,Wit, Jan B.M.,Bickelhaupt, Friedrich,Veldman, Nora,Spek, Anthony L.,Jolly, Peter W.
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p. 107 - 119
(2007/10/03)
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- Chemistry of sterically protected bis(phosphinidene)-cyclobutenes
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Sterically protected low-coordinated phosphorus-containing cyclobutenes were prepared and characterized as well as [4]radialenes. The reactions were studied involving E/Z isomerization, transition-metal complex formation, and coupling reactions catalyzed
- Yoshifuji, Masaaki,Toyota, Kozo
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p. 589 - 592
(2007/10/03)
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- A New Preparative Route to Phosphaethynes from Dichlorophosphaethenes by Lithiation, Photoisomerization, and Re-lithiation Involving Migration
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2-(2,4,6-Tri-t-butylphenyl)-1-phosphaethyne was prepared from 2,2-dichloro-1-(2,4,6-tri-t-butylphenyl)-1-phosphaethene by lithiation of anti-chloro atom followed by hydrolysis, photoisomerization, and repeated lithiation involving migration.The present me
- Yoshifuji, Masaaki,Kawanami, Hajime,Kawai, Yoshinori,Toyota, Kozo,Yasunami, Masafumi,et al.
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p. 1053 - 1056
(2007/10/02)
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- Synthesis and Reactions of P-Supermesityl-C-halophosphaalkenes
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C-Halophosphaalkenes (1, 2) were prepared in high yield by a one-pot synthesis from HCX3 or CI4 and Mes*PCl2 (Mes* = supermesityl = 2,4,6-tri-tert-butylphenyl).The C-iodophosphoaalkenes Mes*P=Cl2 (1c) and Mes*P=CHI (2c) undergo halogen-metal exchange with n-BuLi at low temperatures.The resulting carbenoids Mes*P=CILi (11c) and Mes*P=CHLi (6) reacted with ClMMe3 (M = Si, Ge, Sn) to give Mes*P=CIMMe3 or Mes*P=CHMMe3 (8-10), respectively.Further reaction of (Z)-13 and (Z)-14 with n-BuLi and ClMMe3 gave Mes*P=C(MMe3)2 (18: M = Ge; 19: M = Sn).The carbenoid (Z)-11c decomposed at -85 deg C; instead of the expected "phosphaisonitrile" Mes*P=C: (21), only Mes*CP (15) was obtained which lends experimental support to the theoretically predicted instability of 21.Key Words: Phosphaalkenes, C-halo, C-metal / "Phospha-isonitrile" / Phosphinylidenemethylene / Phosphaalkyne, E/Z isomers
- Goede, Simon J.,Bickelhaupt, Friedrich
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p. 2677 - 2684
(2007/10/02)
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- Formation of a Phospha-alkyne via Migration of the Phenyl Group from Phosphorus to Carbon
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E-2-Chloro-1-(2,4,6-tri-t-butylphenyl)-1-phospha-ethylene was allowed to react with t-butyllithium as a base to give 2-(2,4,6-tri-t-butylphenyl)-1-phospha-acetylene, suggesting the generation of a phosphorus analogue of isonitrile followed by migration of
- Yoshifuji, Masaaki,Niitsu, Takashi,Inamoto, Naoki
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p. 1733 - 1734
(2007/10/02)
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- DI--PHOSPHAN, DI--ARSAN - KETO-ENOL-TAUTOMERIE
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By reaction of (2,4,6-tri-tert-butyl)-benzoylchloride with lithium-(bis-trimethylsilyl)-phosphide resp. lithium-(bis-trimethylsilyl)-arsenide the title compounds are prepared.
- Maerkl, G.,Sejpka, H.
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p. 1771 - 1774
(2007/10/02)
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