- Synthesis and properties of new phosphorescent red light-excitable platinum(II) and palladium(II) complexes with schiff bases for oxygen sensing and triplet-triplet annihilation-based upconversion
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New Pt(II) and Pd(II) complexes with donor-acceptor Schiff bases are conveniently prepared in only two steps. The complexes efficiently absorb in the red part of the spectrum (ε > 105 M-1 cm -1) and show moderate to strong
- Borisov, Sergey M.,Saf, Robert,Fischer, Roland,Klimant, Ingo
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- Palladium(II)-pivaloyl thiourea complexes: Synthesis, characterisation and their catalytic activity in mild Sonogashira cross-coupling reaction
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We report herein the synthesis of Pd(II) complexes featuring pivaloylthiourea derivatives to investigate their catalytic behaviour in Sonogashira cross-coupling reactions as the homogenous catalyst. The SN2 reactions have resulted in pivaloyl thiourea derivatives ligands with general formula (CH3)3C(O)NHC(S)NHR introducing different substituent groups of NO2 (L1), OCH3 (L2), and H (L3) prior to form complexation with Pd(II) (MC1, MC2, and MC3 respectively). All synthesised compounds were characterised via typical selected spectroscopic and analytical methods. Hence, catalytic screening activity revealed that Pd(II)-pivaloyl thiourea catalysed, featuring MC3, is the best catalyst as it gave a high conversion rate up to 99%.
- Khairul, Wan M.,Wahab, Falynee Faha Abdul,Soh, Siti Kamilah Che,Shamsuddin, Mustaffa,Daud, Adibah Izzati
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- Anchoring of Pd on silica functionalized with nitrogen containing chelating groups and applications in catalysis
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Pd-complexes of silica-anchored nitrogen containing chelating compounds were prepared by the following reactions: (a) synthesis of the Schiff-bases from 3-aminopropyltriethoxysilane and 2-acetylpyridine, 2-acetylpyrazine or 2,6-diacetylpyridine; (b) reduction of the Schiff-bases with NaBH4 in methanol; (c) cogelification with tetraethyl orthosilicate (TEOS); (d) reaction of the obtained functionalized silica with [PdCl2(PhCN)2] in CH2Cl2. The corresponding model ligands and palladium complexes were also prepared from the reaction of n-propylamine with the pyridine or pyrazine compound, followed by the reduction with NaBH4 and the reaction with [PdCl2(PhCN)2]. The products were characterized by BET, FTIR, GC-MS, 1H-NMR and elemental C-H-N analysis. The anchored Pd-complexes were tested as catalysts in: (a) the Heck reaction of iodobenzene with ethyl acrylate or styrene in the presence of tributylamine, as base, and toluene or p-xylene, as solvent; (b) the carbonylation reaction of iodobenzene with CO, at atmospheric pressure, in methanol in the presence of triethylamine or potassium acetate, as base. The catalysts were separated from the reaction mixtures and re-used many times. The best results were obtained in both reactions with the anchored Pd-complexes prepared from 2-acetylpyridine: 14 cycles in the Heck reaction (TON ? 4100 mmol product/mmol Pd) and 20 cycles in the carbonylation of iodobenzene (TON ? 2300 mmol product/mmol Pd).
- Lagasi, Matteo,Moggi, Pietro
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- Soluble polysiloxane-supported palladium catalysts for the Mizoroki-Heck reaction
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Soluble polysiloxanes of various architectures (linear, star-shaped and hyperbranched), having vinyl, 2-butylthioethyl and 2-diphenylphosphinoethyl side groups have been used as supports for palladium(II) catalysts. Catalytic activity of such immobilized palladium complexes was tested in model Mizoroki-Heck reactions. The activity of the complexes in terms of yield and turnover number was comparable to that of PdCl2(PhCN)2. Polysiloxane-supported catalysts show good stability and can be reused several times. Catalysts immobilized on linear polymers show generally better stability than those immobilized on branched structures. Mercury poisoning test indicated that the true catalytic species is the supported complex. According to XPS analysis, palladium in the complexes with polysiloxanes is present as Pd(II). XRF shows however a significant metal leaching after 5-10 reaction cycles.
- Cypryk, Marek,Pospiech, Piotr,Strzelec, Krzysztof,Wasikowska, Karolina,Sobczak, Janusz W.
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- Studies of thermal decomposition of palladium(II) complexes with olefin ligands
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PdCl2(VTMS)2 (1), PdCl2(PTMSA)2 (2), PdCl2(DMB)2 (3) and PdCl2(DADMS)2 (4), where VTMS-trimethyl(vinyl)silane, DADMS-diallyldimethylsilane, PTMSA-1-phenyl-2
- Sz?yk,Barwio?ek
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- Preparation method of bis (cyanobenzene) palladium dichloride
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The invention discloses a preparation method of bis (cyanobenzene) palladium dichloride, which comprises the following steps: (1) dissolving palladium powder in aqua regia to prepare a palladium active group, cooling, and mixing with benzonitrile; (2) distilling to remove moisture, heating to react, and carrying out hot filtration; and (3) cooling the filtrate, adding the cooled filtrate into an organic solvent, separating out a solid, filtering, washing the obtained filter cake with the organic solvent, and carrying out vacuum drying. According to the method provided by the invention, palladium powder is used as a raw material to replace palladium chloride in the prior art, so that the reaction cost is reduced, and the prepared product is high in purity and high in yield.
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Paragraph 0011-0017
(2021/04/03)
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- Synthesis of a Bolm's 2,2′-Bipyridine Ligand Analogue and Its Applications
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A new method of synthesis of an analogue of Bolm's 2,2′-bipyridine ligand based on the catalytic [2+2+2] cyclotrimerization of 1-halodiynes with nitriles was developed. Crucial step of the whole synthesis turned out to be homodimerization of a substituted 2-bromopyridine to the corresponding bipyridine, that was studied and optimized. The newly prepared bipyridine (S,S)-2 was then tested as a chiral ligand in metal-catalyzed enantioselective reactions. Out of the studied reactions the most promising results were obtained in epoxide ring opening (82% yield, 98% ee) and Mukaiyama aldol reaction (>96% yield, 99/1 dr, 92% ee). In the case of Mukaiyama-aldol reaction as well as in the Michael addition, novel ligand 2 proved its robustness compared to Bolm's ligand as it was less sensitive to the purity of used reagents. (Figure presented.).
- Bedná?ová, Eva,Dra?ínsky, Martin,Malatinec, ?tefan,Císa?ová, Ivana,Lamaty, Frédéric,Kotora, Martin
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supporting information
p. 2869 - 2878
(2018/08/17)
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- Pt(II) and Pd(II)-assisted coupling of nitriles and 1,3-diiminoisoindoline: Synthesis and luminescence properties of (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) and Pd(II) complexes
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Treatment of trans-[PtCl2(NCR)2] 1 (R?=?Me (1a), Et (1b), o-ClC6H4 (1c), p-ClC6H4 (1d), p-(HC[dbnd]O)C6H4 (1e), p-O2NC6H4CH2 (1f)) with 1,3-diiminoisoindoline HN[dbnd]CC6H4C(NH)[dbnd]NH 2 gives access to the corresponding (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pt(II) complexes [PtCl{NH[dbnd]C(R)N[dbnd]C(C6H4)NC[dbnd]NC(R)[dbnd]NH}] 3a–f, in good yields (65–70%). The reaction of trans-[PdCl2(NCMe)2] 4a with 2 furnishes (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato)Pd(II) complex [PdCl{NH[dbnd]C(Me)N[dbnd]C(C6H4)NC[dbnd]NC(Me)[dbnd]NH}] 5a, in good yield (65%). However, the reaction of trans-[PdCl2(NCR)2] 4 (R?=?Ph (4b), p-MeC6H4CH2 (4c), p-(HC[dbnd]O)C6H4 (4d), p-O2NC6H4CH2 (4e)) with 2 gives a number of unidentified products. The compounds 3a–f and 5a were characterized by IR,1H,13C and DEPT-135 NMR spectroscopies, elemental analyses and, in the case of the Pt(II) complex [PtCl{NH[dbnd]C(Me)N[dbnd]C(C6H4)NC[dbnd]NC(Me)[dbnd]NH}] 3a, also by X-ray diffraction analysis. Compounds 3a and 3b were also characterized by UV–Vis absorption and luminescence emission spectroscopies. Emission quantum yields of ca. 3?×?10?3 were obtained in dichloromethane solution, and luminescence lifetimes are in the order of the tens of nanoseconds. Both compounds also exhibited luminescence in solid state (polystyrene matrix), with luminescence lifetimes in the order of hundreds of nanoseconds.
- Lasri, Jamal,Pedras, Bruno,Haukka, Matti,Berberan-Santos, Mário N.
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p. 195 - 202
(2017/06/13)
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- Preparation and application of coconut shell activated carbon immobilized palladium complexes
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Coconut shell activated carbon (CSAC) granules were used as carriers to immobilize palladium complexes. Boehm titration showed that the hydroxyl content of the carbon surface reached 0.376 mmol g-1 after 20% HNO 3 treatment. Ethylenediamine, benzyl malononitrile and propyl malononitrile were successfully grafted onto the oxidized CSAC. The bidentate nitrogen ligands complexed Pd2+ samples were characterized by FT-IR, XPS, ICP and N2 adsorption-desorption. In oxidative carbonylation of phenol, three bidentate ligand grafted catalysts were evaluated in a high pressure reaction vessel. The results showed that the ethylenediamine grafted catalyst had a phenol conversion of 12.06% and a diphenyl carbonate (DPC) selectivity of 91.03%. In comparison, the benzyl malononitrile grafted catalyst displayed a phenol conversion of 12.00% and a DPC selectivity of 90.65%. The propyl malononitrile grafted catalyst displayed a phenol conversion of 6.22% and a DPC selectivity of 81.02%. Additionally, the ethylenediamine and the benzyl malononitrile grafted catalysts were also investigated in a continuous packed-bed reactor. The results showed that the phenol conversion and the DPC selectivity were comparative to those obtained in a high pressure reaction vessel. This journal is the Partner Organisations 2014.
- Zhang, Yulian,Xiang, Shuanglong,Wang, Guoqing,Jiang, Hong,Xiong, Chunrong
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p. 1055 - 1063
(2014/04/03)
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- Palladium catalysed alkyne hydrogenation and oligomerisation: A parahydrogen based NMR investigation
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The role phosphine ligands play in the palladium(ii)-bis-phosphine-hydride cation catalysed hydrogenation of diphenylacetylene is explored through a PHIP (parahydrogen induced polarization) NMR study. The precursors Pd(LL′)(OTf)2 (1a-e) [LL′ = dcpe (PCy2CH 2CH2PCy2), dppe, dppm, dppp, cppe (PCy 2CH2CH2PPh2)] are used. Alkyl palladium intermediates of the type [Pd(LL′)(CHPhCH2Ph)](OTf) (2 and 3) are detected and demonstrated to play an active role in hydrogenation catalysis. Magnetization transfer experiments reveal chemical exchange from the α-H of the alkyl ligand of 2a (LL′ = dcpe) and linkage isomer 2e′ (LL′ = cppe) into trans-stilbene on the NMR timescale. Activation parameters (ΔH≠ and ΔS≠) for this transformation have been determined. These experiments, coupled with GC/MS data, indicate that the catalytic activity is greater in methanol, where it follows the order: dcpe > cppe > dppp > dppe > dppm, than in CD 2Cl2. All five of the phosphine systems described are less active than those based on bcope [where bcope is (C8H 14)PCH2-CH2P(C8H14)] and tbucope [where tbucope is (C8H 14)PC6H4CH2P(tBu) 2]. cis, cis-1,2,3,4-Tetraphenyl-buta-1,3-diene is detected as a minor reaction product with Pd(LL′)(PhCH-CHPh-CPh=CHPh)+ (4) also being shown to play a role in the alkyne dimerisation step.
- Lopez-Serrano, Joaquin,Duckett, Simon B.,Dunne, John P.,Godard, Cyril,Whitwood, Adrian C.
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p. 4270 - 4281
(2009/02/03)
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- 1,1-Ethylenedithiolato complexes of palladium(II) and platinum(II) with isocyanide and carbene ligands
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The reactions of [Tl2{S2C=C{C(O)Me}2}]n with [MCl2(NCPh)2] and CNR (1:1:2) give complexes [M{η2-S2C= C{C(O)Me}2}(CNR)2] [R = tBu, M = Pd (1a), Pt (1b); R = C6H3Me2-2,6 (Xy), M = Pd (2a), Pt (2b)]. Compound 1b reacts with AgClO4 (1:1) to give [{Pt(CNtBu)2}2Ag2 {μ2,η2-(S,S′)-{S2C=C{C(O) Me}2}2}](ClO4)2 (3). The reactions of 1 or 2 with diethylamine give mixed isocyanide carbene complexes [M{η2-S2C=C{C(O)Me}2}(CNR)-{C (NEt2)(NHR)}] [R = tBu, M = Pd (4a), Pt (4b); R = Xy, M = Pd (5a), Pt (5b)] regardless of the molar ratic of the reagents. The same complexes react with an excess of ammonia to give [M{η2-(S,S′)-S2C=C{C(O)Me}2}- (CNtBu){C(NH2)(NHtBu)}] [M = Pd (6a), Pt (6b)] or [M{η2-(S,S′)-S2C=C{C(O)Me}2}{C (NH2)(NHXy)}2] [M = Pd (7a), Pt (7b)] probably depending on steric factors. The crystal structures of 2b, 4a, and 4b have been determined. Compounds 4a and 4b are isostructural. They all display distorted square planar metal environments and chelating planar E,Z-2,2-diacetyl-1,1-ethylenedithiolato ligands that coordinate through the sulfur atoms.
- Vicente, Jose,Chicote, Maria Teresa,Huertas, Sonia,Jones, Peter G.
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p. 4268 - 4274
(2008/10/08)
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- Preparation of the first complexes of bidentate sulfimides; the X-ray crystal structures of [PdBr2{1,4-(PhS{NH})2C6H4}] 2, [PdCl2{1,2-(PhS{NH})(PhS)C6H4}] and trans-[PdCl2{1,2-(PhS{NH})(PhS)C6H4} PPh3]
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Reaction of [PPh4]2[Pd2X6] (where X = Cl, Br or I) with 1,4-(PhS{NH})2C6H4 (1) in dichloromethane results in the formation of [Pd{1,4-(PhS{NH})2C6H4}X2] 2 (2). X-ray crystallography (performed using a synchrotron source) confirms that in the case where X = Br (2a) both the bis-sulfimides act as bridging ligands through N-Pd bonds producing an 18-membered ring system linking the four sulfur atoms into an almost perfect square. Changing the reaction solvent to methanol/dichloromethane results in the formation of a polymeric material. Reaction of [PdCl2(PhCN)2] with 1,2-(PhS{NH})-(PhS)C6H4 (3) results in the formation of [PdCl2{1,2-(PhS{NH})(PhS)C6H4}] (4) in which 3 acts as a bidentate ligand, bound by N-Pd and S-Pd bonds to form a unique MSCCSN metallacycle. The Pd-S bond is broken upon reaction with one equivalent of PPh3, generating trans-[PdCl2{1,2-(PhS{NH})(PhS)C6H4} PPh3] (5); further reaction with PPh3 results in complete removal of 3 from the system and formation of trans-[PdCl2(PPh3)2]. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Elsegood, Mark R. J.,Holmes, Kathryn E.,Kelly, Paul F.,MacLean, Elizabeth J.,Parr, Jonathon,Stonehouse, Julia M.
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p. 120 - 127
(2007/10/03)
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- Coupling of aryl halides with aryl boronic acids with P(C6H5)(2-C6H4Cl)2 as the supporting ligand
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The chlorinated triarylphosphine P(C6H5)(2-C6H4Cl)2 (1) has been used as a supporting ligand in the Suzuki-Miyaura coupling of aryl boronic acids with aryl halides. Aryl bromides without ortho substituents were successfully coupled at room temperature, while reactions involving sterically hindered aryl bromides required slight heating (70°C). Electron-deficient aryl chlorides were also successfully coupled with heating (90°C). Key reaction parameters such as order of addition, choice of mineral base, solvent volume, temperature, 1/Pd ratio, as well as electronic and steric variation of the aryl halide have been investigated and are reported.
- Pramick, Michelle R.,Rosemeier, Sara M.,Beranek, Maryann T.,Nickse, Stephanie B.,Stone, Joshua J.,Stockland Jr., Robert A.,Baldwin, Steven M.,Kastner, Margaret E.
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p. 523 - 528
(2008/10/08)
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- New monocationic methylpalladium(II) compounds with several bidentate nitrogen-donor ligands: Synthesis, characterisation and reactivity with CO
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Two series of methylpalladium(II) compounds with mono and bidentate nitrogen-donor ligands, namely [Pd(N-N)2(CH3)][X] (N-N=phen (1a), dm-phen (1b) (dm-phen=4,7-dimethyl-1,10-phenanthroline), tm-phen 1c (tm-phen=3,4,7,8-tetramethyl-1,10-phenanthroline); X=OTf, PF6-) and [Pd(N-N)(L)(CH3)][OTf] (N-N=phen and L=py (1ad) (py=pyridine), N-N=phen and L=2-Ph-py (1ae) (2-Ph-py=2-phenyl-pyridine), N-N=phen and L=BzQ (1af) (BzQ=7,8-benzoquinoline), N-N=tm-phen and L=BzQ (1cf)), have been synthesised and fully characterised both in solid state and in solution. The crystal structures of [Pd(phen)2(CH3)][PF6] and [Pd(phen)(2-Ph-py)(CH3)][OTf] show a square planar coordination geometry for palladium with the monodentate ligand (one phen molecule plays this role in 1a) bound to the metal with its plane almost perpendicular to the coordination plane. In both structures the Pd-N bond length trans to the methyl is remarkably affected by its trans influence. The behaviour in solution is characterised for the first series of compounds by a dynamic process which makes the two N-N ligands equivalent, as corroborated by the 15N NMR analysis: only one averaged signal is shown for all of the four nitrogen atoms. No fluxional process is present for the compounds of the second series, and three main crosspeaks are shown in the 15N-1H HMQC spectra. In particular, the signal of the 15N trans to the methyl group has a typical chemical shift, which differs from those of two 15N trans to each other. Both series of complexes are reacted with carbon monoxide and the reaction products are studied by 1H NMR spectroscopy and, when possible, by isolating the acyl derivatives. The products of this reaction are affected by the nature of the second molecule of N-ligand.
- Milani, Barbara,Marson, Angelica,Zangrando, Ennio,Mestroni, Giovanni,Ernsting, Jan Meine,Elsevier, Cornelis J
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p. 188 - 201
(2008/10/08)
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- Syntheses, structures and properties of palladium(II) complexes with photochromic 4-methoxyazobenzene
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Two palladium(II) complexes with the photochromic ligand 4-methoxyazobenzene (MeOazbH), [Pd(MeOazb) (PhCN) (H2O)] (ClO4) (1) and [Pd(MeOaZbH)2Cl2] (2) were prepared and their molecular structures determined by X-ray crystallography. 1: triclinic, P1, a = 9.684(3), b =11.833(2), c = 9.731(3) A, α = 102.41(1), β = 94.54(3), γ =94.82(2)°, V = 1079.7(4) A3, Z =2. 2: triclinic, P1, a = 9.497(3), b = 9.719(4), c = 8.226(3) A, α = 96.43(4), β= 109.24(3), γ =62.13(2)°, V = 632.9(4) A3, Z= 1. The molecular structure of complex 1 shows a significantly distorted square planar coordination around the Pd atom and the MeOazb group forms a five-membered chelate ring with the metal ion by means of a σ-bond at an ortho-carbon atom and the lone pair of the further nitrogen. In complex 2 the palladium atom lies on an inversion center, surrounded in an essentially square planar fashion by the symmetry related two MeOazbH ligands and two chloride ions. In contrast with the ortho-metalation reaction in 1, MeOazbH in 2 acts as a monodentate ligand to bind the metal center via a Pd-N σ-bond. Electronic spectroscopic studies of the two complexes together with the free ligand were carried out in solution at room temperature and upon irradiation of light; while rigidity imparted to the MeOazb linkage by palladation in 1 inhibits its photochromic reaction, the monodentate-coordinated MeOazbH in 2 shows a trans-cis photoisomerization.
- Wu, Liang Ping,Suenaga, Yusaku,Kuroda-Sowa, Takayoshi,Maekawa, Masahiko,Furuichi, Koji,Munakata, Megumu
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p. 147 - 152
(2008/10/08)
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- The Stereochemistry of Organometallic Compounds. XXIX Synthesis of Stereoidal 1,4-, 1,3- and 1,6-Diphosphines and Their Evaluation as Ligands in Metal-Catalyzed Asymmetric Synthesis
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The steroidal 1,4-diphosphines 3α- and 3β-diphenylphosphino-2α-(2'-diphenylphosphinoethyl)-5α-cholestanes and their 5H-benzophosphindole derivatives have been prepared and shown to be useful ligands in asymmetric hydrogenation reactions.Interestingly the 3α- and 3β-derivatives lead to opposing enantioselection preferences when used in these reactions.A steroidal 1,3-diphospine, 3α-diphenylphosphino-2α-diphenylphosphinomethyl-5α-cholestane, has been prepared as a mixture containing some of the 3β-epimer.The 3α-1,3-diphosphine led to similar enantioselection in hydrogenation reactions as the 3α-1,4-diphosphine, and a model is proposed to explain the sense of the enantioselectivity in the 1,4- and 1,3-diphosphines.A steroidal 1,6-diphosphine has also been prepared but leads to lower optical yields in the hydrogenation reactions.These ligands have been shown to lead to only poor to moderate optical yields when used in asymmetric carbon-carbon bond forming reactions.
- Thomson, Robin J.,Jackson, W. Roy,Haarburger, David,Klabunovsky, Evgeny I.,Pavlov, Valery A.
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p. 1083 - 1106
(2007/10/02)
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