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Search for "phosphines" in Full Text gives 106 result(s) in Beilstein Journal of Organic Chemistry.

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

  • Andrea Caporale,
  • Stefano Tartaggia,
  • Andrea Castellin and
  • Ottorino De Lucchi

Beilstein J. Org. Chem. 2014, 10, 384–393, doi:10.3762/bjoc.10.36

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  • with P(p-tol)3 allowed to obtain 2a in 89% yield (Table 1, entry 9), whereas other monodentate or chelating phosphines displayed a lower efficiency. Pd sources other than Pd(OAc)2 were also used but did not show positive effects. Having thus found an optimized method for the cooper free palladium
  • , entry 5) resulted the best ligand with respect to XPhos (Table 3, entry 7), whereas other simple monodentate phosphines, such as Pt-Bu3 or PPh3, seem not to be able to promote efficiently the reaction (data not shown). The change of the Pd source to Pd2(dba)3 led to a further increase of the yield up to
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Published 12 Feb 2014

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

  • Peter H. Huy,
  • Julia C. Westphal and
  • Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

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  • to provide sufficient substance amounts for clinical tests [41][42]. Additionally, alternatives in reactions driven by the formation of phosphine oxides from phosphines (e.g. the Appel and Mitsunobu reaction) are highly desired to improve atom economy (reduced waste amounts) and to circumvent
  • difficulties in the separation of these by-products as demonstrated by a number of reviews [43][44][45]. Numerous protocols have been developed to improve these issues, mostly based on polymer supported or otherwise modified (more complex) phosphines [43][44][45]. Surprisingly, in this context simple and
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Published 11 Feb 2014

Cyclic phosphonium ionic liquids

  • Sharon I. Lall-Ramnarine,
  • Joshua A. Mukhlall,
  • James F. Wishart,
  • Robert R. Engel,
  • Alicia R. Romeo,
  • Masao Gohdo,
  • Sharon Ramati,
  • Marc Berman and
  • Sophia N. Suarez

Beilstein J. Org. Chem. 2014, 10, 271–275, doi:10.3762/bjoc.10.22

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  • , BrMg(CH2)4MgBr and BrMg(CH2)5MgBr respectively. The resultant cyclic phosphines are air sensitive and therefore were allowed to react with BH3·THF to provide the air-stable 1-n-butylphospholane–borane and 1-n-butylphosphinane–borane complexes that were purified by silica-gel chromatography. The pure
  • compounds were then treated under nitrogen with 1,4-diazabicyclo[2.2.2]octane (DABCO) at 80 °C to remove the borane, and the resultant mixture was purified in a nitrogen-filled glove box on a short silica-gel column. The pure cyclic phosphines (1-n-butylphospholane and 1-n-butylphosphinane) were allowed to
  • silica gel. Both cyclic phosphines were each allowed to react with 1-bromobutane at reflux under nitrogen to give the 1-n-butyl-1-phenylphospholanium bromide (4c) and the 1-n-butyl-1-phenylphosphinanium bromide (4d), respectively. Each of these salts was then mixed with aqueous LiNTf2 to form the 1-n
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Published 24 Jan 2014

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

  • Phei Li Lau,
  • Ray W. K. Allen and
  • Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

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  • reactions have been performed using homogeneous palladium catalysts with added phosphines, either as free reagents, coordinated discrete ligands or built into the ligand system itself. In recent years there has been a drive to develop phosphine-free catalysts and systems to ease separation and reduce both
  • ]. The majority of the examples of catalysts discussed employ phosphines as electron-donating ligands but this is undesirable as they are toxic, air-sensitive, and moisture-sensitive [32]. An excess amount of phosphine and palladium are normally required under the Heck reaction conditions as they are
  • solvent system used was a mixture of scCO2 and THF/methanol which contained the alkene and the organic base, DIPEA. In order to reduce the complexity of the system, palladium metal supported on silica was used as catalyst and no phosphines were added. While this was likely to reduce the activity of the
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Published 17 Dec 2013

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

  • Regina Berg and
  • Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

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Published 02 Dec 2013

Organocatalyzed enantioselective desymmetrization of aziridines and epoxides

  • Ping-An Wang

Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192

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  • enantioselectivities. In the presence of some achiral phase-transfer catalysts or phosphines such as TBAB and P(t-Bu)3, the vicinal chlorohydrins were obtained in high yields. Up to now, three classes of organocatalysts including chiral phosphoramides, chiral phosphine oxides, and chiral pyridine N-oxides were used in
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Published 15 Aug 2013

Palladium(II)-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

  • Tanveer Mahamadali Shaikh and
  • Fung-E Hong

Beilstein J. Org. Chem. 2013, 9, 1578–1588, doi:10.3762/bjoc.9.180

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  • substrates [12][13][14][15][16]. The class of phosphine-ligated palladium complexes [17][18][19][20][21] represents the most frequently employed precatalysts to achieve high reactivities and selectivities for such reactions. However, such trisubstituted phosphines in the palladium complexes are often air
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Published 05 Aug 2013

Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

  • Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 1269–1277, doi:10.3762/bjoc.9.143

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  • phosphorus always culminates in difunctionalization of a multiple bond. Therefore this methodology will find application in the synthesis of complex phosphines including bidentate ones. Radical substitution of halogen in organic halide with phosphorus will be an alternative to classical ionic substitution
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Published 28 Jun 2013

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

  • Stefan Riedmüller and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

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  • angle of the phosphines 99° and 93°, respectively) (Table 1, entry 5 and 7). When using bidentate ligands with bite angles higher than 100° (DPEphos 104°, Xantphos 108°) the reaction is more efficient and the yield increases significantly. Next, we asked ourselves, whether other palladium salts could be
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Published 21 Jun 2013

Asymmetric Diels–Alder reaction with >C=P– functionality of the 2-phosphaindolizine-η1-P-aluminium(O-menthoxy) dichloride complex: experimental and theoretical results

  • Rajendra K. Jangid,
  • Nidhi Sogani,
  • Neelima Gupta,
  • Raj K. Bansal,
  • Moritz von Hopffgarten and
  • Gernot Frenking

Beilstein J. Org. Chem. 2013, 9, 392–400, doi:10.3762/bjoc.9.40

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  • chiral auxiliaries [3][4]. Chiral phosphines constitute a very important group of ligands as their coordination compounds with transition metals have been extensively employed in asymmetric catalysis to convert achiral compounds into enantio-enriched products with high efficiency and enantioselectivity
  • [5]. In many cases, chiral monophosphine ligands have been found to be more useful than chiral bisphosphines [6][7][8]. In view of this, efforts are always being made to obtain new chiral phosphines [9]. The first example of the Diels–Alder (DA) reaction with the >C=P– functionality of an
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Published 18 Feb 2013

N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides

  • Ismail Özdemir,
  • Nevin Gürbüz,
  • Nazan Kaloğlu,
  • Öznur Doğan,
  • Murat Kaloğlu,
  • Christian Bruneau and
  • Henri Doucet

Beilstein J. Org. Chem. 2013, 9, 303–312, doi:10.3762/bjoc.9.35

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  • coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides
  • ligands, which are electronically and sterically tunable, and which generally form thermally stable compounds with different metal ions, are strong σ-donors. These qualities have rendered N-heterocyclic carbene ligands as classical substitutes to phosphines in organometallic catalysis [10][11][12][13][14
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Published 12 Feb 2013

Alkenes from β-lithiooxyphosphonium ylides generated by trapping α-lithiated terminal epoxides with triphenylphosphine

  • David. M. Hodgson and
  • Rosanne S. D. Persaud

Beilstein J. Org. Chem. 2012, 8, 1896–1900, doi:10.3762/bjoc.8.219

Graphical Abstract
  • way than the above approaches to β-lithiooxyphosphonium ylides 4 (R2 = H), we were attracted to the possibility of phosphines intercepting α-lithiated terminal epoxides 10 (Scheme 2) and report here the results of that study. Such carbenoids 10 are unstable, but they can be easily formed from terminal
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Published 07 Nov 2012

A quantitative approach to nucleophilic organocatalysis

  • Herbert Mayr,
  • Sami Lakhdar,
  • Biplab Maji and
  • Armin R. Ofial

Beilstein J. Org. Chem. 2012, 8, 1458–1478, doi:10.3762/bjoc.8.166

Graphical Abstract
  • (Figure 3d) were linear, with their slopes giving the second-order rate constants k2 (M–1 s–1) [35][36]. For the investigations of reactions of the iminium ions on the micro- and nanosecond time scale, laser flash spectroscopy was employed [37]. As tertiary phosphines PR3 (10) are known to be excellent
  • photonucleofuges [38][39][40][41], the stable iminium salts 3-PF6 were treated with tertiary phosphines 10 at room temperature to give the enamino-phosphonium ions 11 instantaneously (Figure 4a). Their irradiation with 7 ns laser pulses (266 nm) regenerated the iminium ions, the decay of which was monitored
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Published 05 Sep 2012

Chiral multifunctional thiourea-phosphine catalyzed asymmetric [3 + 2] annulation of Morita–Baylis–Hillman carbonates with maleimides

  • Hong-Ping Deng,
  • De Wang,
  • Yin Wei and
  • Min Shi

Beilstein J. Org. Chem. 2012, 8, 1098–1104, doi:10.3762/bjoc.8.121

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  • work of Lu [11][12][13][14][15][16][17][18][19][20], all phosphine-mediated [3 + 2] annulations proceeded through an important intermediate “1,3-dipolar synthon”. The formation of a 1,3-dipolar synthon by using a catalytic amount of phosphines have been directed toward the following two paths
  • : phosphines attack the middle carbon atom of allenes to produce the 1,3-dipolar synthon (Scheme 1, reaction 1), and phosphines add to the β-position of MBH carbonate to remove carbon dioxide and tert-butanol, affording the 1,3-dipolar synthon (Scheme 1, reaction 2). Concerning the asymmetric [3 + 2
  • ] annulation catalyzed by chiral phosphines, Zhang and co-workers first reported the asymmetric [3 + 2] annulation of allenoates with acrylates catalyzed by a bicyclic chiral phosphine in 1997 [21]. Moreover, Fu [22][23][24], Marinetti [25][26][27][28], Lu [29][30][31] and other researchers [32][33][34][35][36
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Published 16 Jul 2012

Fifty years of oxacalix[3]arenes: A review

  • Kevin Cottet,
  • Paula M. Marcos and
  • Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

Graphical Abstract
  • highly atypical but may be due to the templating effect of Na+. Separation by column chromatography afforded the cone conformer in 72% yield although the partial-cone was never obtained in a pure form. Reduction by phenylsilane (PhSiH3) gave the corresponding cone and partial-cone phosphines 26
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Published 07 Feb 2012

Recent developments in gold-catalyzed cycloaddition reactions

  • Fernando López and
  • José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

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  • the possibility of modulating the properties of the metal through modification of its ancillary ligands (e.g., phosphines, N-heterocyclic carbenes, etc.), which considerably widens the potential and versatility of these catalysts, and in particular of those consisting of cationic gold(I) complexes
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Published 09 Aug 2011

Recent advances in the gold-catalyzed additions to C–C multiple bonds

  • He Huang,
  • Yu Zhou and
  • Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

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  • was observed by employing alcohol substrates bearing coordination functionalities. In addition, the catalyst system with electron deficient phosphines was also found to catalyze the desired reaction effectively (Scheme 10). An efficient approach [36] for the preparation of unsymmetrical ethers from
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Published 04 Jul 2011

When cyclopropenes meet gold catalysts

  • Frédéric Miege,
  • Christophe Meyer and
  • Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

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  • the desired cyclopropanation product 48, but the yield and the diastereoselectivity were highly dependent on the gold ligand. As anticipated from the structural studies, π-acidic phosphites that increase cation-like reactivity gave little or none of the cyclopropanation product 48. Phosphines gave
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Published 30 May 2011

Studies on Pd/NiFe2O4 catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

  • Sanjay R. Borhade and
  • Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

Graphical Abstract
  • of phosphorous ligands. Efforts have been made to enhance the catalytic activity by the use of various ligands containing nitrogen or sulfur, as well as phosphines, salen and N-heterocyclic carbenes in traditional organic solvents [12][13][14][15][16][17][18][19]. However, the problems associated
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Published 15 Mar 2011

Synthesis of Ru alkylidene complexes

  • Renat Kadyrov and
  • Anna Rosiak

Beilstein J. Org. Chem. 2011, 7, 104–110, doi:10.3762/bjoc.7.14

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  • precursors for the “second generation” catalysts bearing NHC ligands are the alkylidene ruthenium complexes coordinated with two phosphines [1]. For recent reviews see [2][3][4]. There are several routes for accessing five-coordinated ruthenium(II) alkylidene complexes such as diazo-transfer [5] and the
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Published 21 Jan 2011

Olefin metathesis in nano-sized systems

  • Didier Astruc,
  • Abdou K. Diallo,
  • Sylvain Gatard,
  • Liyuan Liang,
  • Cátia Ornelas,
  • Victor Martinez,
  • Denise Méry and
  • Jaime Ruiz

Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13

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  • chelating phosphine ligands on the branch termini. The choice of chelating phosphines may seem counter-intuitive, because the activity of Grubbs catalysts involves the decoordination of a phosphine from these trans-bis-phosphine complexes [15]. However, studies by the groups of Hofmann [16][17][18], Fog [19
  • ][20] and Leitner [20] had demonstrated the metathesis activity of cis-bis-phosphine ruthenium benzylidene catalysts. We therefore used Reetz’s bis-phosphines derived from the commercial polyamine DSM dendrimers [21]. These dendritic bis-phosphines are useful and versatile in metallodendritic catalysis
  • and provided the first recyclable metallodendritic catalysts [21]. Moreover, dendritic bis-phosphines with two phenyl groups on each phosphorus atom very cleanly yielded the first dendrimers decorated with clusters at the periphery via an efficient electron-transfer-chain reaction using [Ru3(CO)12
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Published 19 Jan 2011

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

  • Carolin Fischer and
  • Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

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  • -aryl bond formation, and many examples illustrate their wide application in organic synthesis. The chelating phosphines BINAP, DPPF [17] and DtBPF [18], commonly used for the Buchwald–Hartwig amination, were recently displaced by the biaryl-(dialkyl)phosphine or arylphosphinepyrrole ligands [18][19][20
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Published 14 Jan 2011

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

  • Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

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Published 18 Aug 2010

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

  • Norio Shibata,
  • Andrej Matsnev and
  • Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

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  • in situ (a carboxylate from 35 and an alcoholate from 37). P-Trifluoromethyl phosphines were formed in moderate to high yields from either diarylphosphines or P-trimethylsilylated derivatives under the same reaction conditions (Scheme 30). By contrast, the corresponding lithium and potassium
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Published 16 Jun 2010

Pd-catalyzed decarboxylative Heck vinylation of 2-nitrobenzoates in the presence of CuF2

  • Lukas J. Gooßen,
  • Bettina Zimmermann and
  • Thomas Knauber

Beilstein J. Org. Chem. 2010, 6, No. 43, doi:10.3762/bjoc.6.43

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  • the catalyst system, and discovered that phosphines impede the decarboxylation step. In contrast, nitrogen-containing ligands had a beneficial effect (entries 16–18). In the presence of 1,4,5-triazanaphthalene, the Heck product was formed in 67% yield (entry 18). We subsequently tested several
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Published 03 May 2010
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