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1.
Trifluoroacetamido-protected β-aminoalkylzinc iodides undergo Negishi cross-coupling reaction with aryl iodides in moderate to excellent yields (42-84%) based on the corresponding trifluoroacetamido-protected β-aminoalkyl iodides, employing a catalyst prepared in situ from Pd2(dba)3 and SPhos (1:2 M ratio). In general, meta- and para-substituted aryl iodides give good results using relatively low levels of catalyst [0.25 mol % Pd2(dba)3], but more hindered ortho-substituted examples require higher catalyst loadings. The preparation of trifluoroacetamido-protected β-aminoalkyl iodides is straightforward, and the intermediates are significantly more stable than the corresponding Boc-protected derivatives. 相似文献
2.
Triphenylantimony dicarboxylates Ph3Sb(OAc)2 and Ph3Sb(O2CEt)2 are efficient C-phenylating agents for methyl acrylate. In the presence of the Pd(OAc)2, Li2PdCl4 or Pd2(dba)3(CHCl3) catalysts in MeCN at 50 °C, methyl cinnamate forms in 70—150% yield with respect to SbV. Copper(ii) salts do not increase the reaction yield. 相似文献
3.
In this paper, taking Pd2(dba)3 as catalyst and 2,2??-bis-(diphenylphosphino)-1,1??-binaphtyl as ligand, six kinds of poly(imino ketone)s (PIKs) with different structures have been synthesized via palladium catalysis C-N cross-coupling reaction. The structures of polymers synthesized was characterized by means of FTIR and NMR spectroscopy, the results showed an agreement with the proposed structures. The influential disciplines of monomer concentration and catalysis system to PIKs molecular weight were discussed. Differential scanning calorimetry measurement showed that PIKs possessed high glass transition temperatures (T g > 150°C). 相似文献
4.
Edgars bele Kira Rubina Mendel Fleisher Juris Popelis Pavel Arsenyan Edmunds Lukevics 《应用有机金属化学》2002,16(3):141-147
The Stille reaction of unsymmetric diynes from terminal bromoalkynes with alkynylstannane in the presence of palladium catalyst and cesium fluoride was studied. The system (bromoalkyne: PhC≡CSnMe3:Pd2(dba)3:PPh3:CsF:18‐crown‐6) = (1:1:0.015:0.06:2.2:0.1) in toluene at reflux temperature was found to be the most favored. Products were obtained in 31–100% yields. Correlations between calculated electron density, dipole moments and 13C NMR spectral data of synthesized bromoacetylenes and diynes have been carried out. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
5.
Atsushi Shimojima Hideki Kuge Kazuyuki Kuroda 《Journal of Sol-Gel Science and Technology》2011,57(3):263-268
A mesostructured silica-based material was synthesized by self-assembly of a novel amphiphilic molecule consisting of a well-defined
siloxane head with a double five-ring (D5R) structure and a hydrophobic alkyl tail. A precursor functionalized with ethoxy
groups, C22H45Si10O15(OEt)9 (1), was hydrolyzed under an acidic condition with the retention of the D5R units, leading to the formation of two-dimensional
(2D) hexagonal phase by evaporation-induced self-assembly of amphiphilic hydrolyzed molecules. Solid-state 29Si MAS NMR analysis of the resulting hybrid solid confirmed that the D5R units were cross-linked to form siloxane networks.
Calcination of this hybrid solid gave mesoporous silica with high BET surface area (740 m2 g−1). These results expand the design possibility of silica-based materials at both molecular- and meso-scales, leading to the
bottom up synthesis of hierarchically ordered materials. 相似文献
6.
Sameer Urgaonkar 《Tetrahedron》2004,60(51):11837-11842
The Pd2(dba)3/P(i-BuNCH2CH2)3N (1) catalyst system effectively catalyzes the coupling of aza-crown ethers with electronically diverse aryl chlorides, affording N-aryl-aza-crown ethers in good yields. The Pd2(dba)3/P(i-BuNCH2)3CMe (2) catalyst system containing the more constrained bicyclic triaminophosphine is useful for aryl chlorides possessing base-sensitive ester, nitro, and nitrile functional groups. 相似文献
7.
K. K?ppler U. Scheim F. Keidel U. Just 《Fresenius' Journal of Analytical Chemistry》1996,354(1):21-26
Silicone resins can be used as polymeric precursors in the production of ceramic materials. Cohydrolysis of mixtures of trimethylchlorosilane,
methyldichlorosilane, vinylmethyldichlorosilane and phenyltrichlorosilane leads to the formation of especially suitable polysiloxanes,
but also low-molar mass siloxanes are formed as undesired by-products. The structures of these by-products have been elucidated.
Vaporizable components of the matrix have been isolated by distillation, separated using gas chromatography and identified
by mass spectrometry in EI (electron impact ionization) and CI (chemical ionization with isobutane) mode. The EI mass spectra
of the siloxane oligomers with different numbers of Si-H, Si-phenyl and Si-vinyl groups show characteristic fragments like
Me3Si+, ViMe2Si+, Vi2MeSi+, PhMe2Si+, and Ph2MeSi+, which give a first indication to the structure, but generally do not show molecular peaks. A reliable determination of the
molar mass has been possible considering the CI-ions and CI-fragments [M+1]+, [M−1]+, [M−27]+ and [M−77]+, respectively. The compounds M2DPh,OH and M3TPh have been identified as main components of the investigated siloxane mixture. Besides, numerous linear compounds of the type
M2(DH)n(DVi)m and M2TPh(DH)n(DVi)m M as well as cyclic ones of the structure [MTPh(DH)n(DVi)m] with n, m=0–3 have been indicated.
Received: 3 March 1995/Revised: 25 March 1995/Accepted: 3 April 1995 相似文献
8.
Kouki Matsubara Hiromi Okazaki Misako Senju 《Journal of organometallic chemistry》2006,691(17):3693-3699
Palladium-catalyzed α-arylation of ketones, which can efficiently give coupling products by using appropriate ligands and bases, could be applied to a polycondensation reaction. Stable N-heterocyclic carbenes (NHC) were used as favorable ligands coordinating the Pd catalysts, which were generated in situ from commercially available palladium compounds such as Pd(OAc)2 and Pd2(dba)3 as suitable catalyst precursors in this polymerization. Using small amounts of binary catalysts, poly(aryl alkyl ketone)s were afforded in high yields from haloarylketones in the presence of a base. A primarily prepared palladium catalyst having an NHC ligand, [Pd(OAc)2(NHC)], also efficiently catalyzed the polycondensation, whereas a palladium compound bearing two carbene ligands, [PdX2(NHC)2], did not. 相似文献
9.
A. V. Gushchin E. V. Grunova D. V. Moiseev O. S. Morozov A. S. Shavyrin V. A. Dodonov 《Russian Chemical Bulletin》2003,52(6):1376-1379
Catalytic C-phenylation of methyl acrylate to methyl cinnamate with the Ph4SbX complexes (X = F, Cl, Br, OH, OAc, O2CEt) in the presence of the palladium compounds PdCl2, Pd(OAc)2, Pd2(dba)3, Pd(Ph3P)2Cl2, and Pd(dppf)Cl2 (dba is dibenzylideneacetone and dppf is bis(diphenylphosphinoferrocene)) was studied in organic solvents (MeCN, THF, DMF, MeOH, and AcOH). The highest yield of methyl cinnamate (73% based on the starting organometallic compound) was obtained for the Ph4SbCl—PdCl2 (1 : 0.04) system in acetonitrile. 相似文献
10.
Several (diolefin)M(A) complexes (M = Rh, Ir) were prepared, where AH is 1-phenyl-3-methyl- 4-benzoylpyrazolone-5, a very stable asymmetric analogue of acetylacetone. In these complexes the diolefin could be replaced by one mole of (Ph2PCH2CH2)2, two of CO or of PPh3, or three of CNBut, while 1,10-phenanthroline displaced the chelating ligand to yield [(cyclooctadiene)Rh(phen)]+ (A)?. Some compounds X?Y (X?Y = iodine or MeI) added oxidatively yielding the corresponding trivalent species. Using 31P NMR spectra the presence of the expected steric isomers was detected in (Ph3P)(CO)Rh(A) and in (Ph3P) (CO)Rh(A)(X)(Y). 相似文献
11.
Muhammad Hanif Mukhtiar Hussain Moazzam H. Bhatti Saqib Ali Helen S. Evans 《Structural chemistry》2008,19(5):777-784
Four new complexes, [Ph3Sn(isopropylACDA)] (1), [Ph2SnCl(isopropylACDA)] (2), [Ph3Sn(secbutylACDA)] (3), and [Ph2SnCl(secbutylACDA)] (4), have been prepared from reaction between N-alkylated 2-amino-1-cyclopentene-1-carbodithioic acids (ACDA) with Ph2SnCl2 and Ph3SnCl in 1:1 ratio. All complexes are characterized by FTIR, multinuclear NMR (1H, 13C, and 119Sn) and mass spectrometry. In all complexes, the S–H proton has been removed and coordination takes place through the carbodithioate
moiety. The 119Sn NMR data are consistent with five coordination of tin atom in solution. Complexes 2, 3, and 4 have also been confirmed by single X-ray crystallography. All three crystals are triclinic with space group P − 1. In complexes 2 and 4, the geometry around tin atom is distorted trigonal bipyramidal while in 3 the geometry is in between distorted tetrahedral and trigonal bipyramid. In all three structures, ligands are asymmetrically
coordinated to tin atom. In addition, crystal structures are further stabilized by N–H···S hydrogen bonding. 相似文献
12.
Bogdan Marciniec Karol Szubert Ryszard Fiedorow Ireneusz Kownacki Marek J. Potrzebowski Micha Dutkiewicz Adrian Franczyk 《Journal of molecular catalysis. A, Chemical》2009,310(1-2):9-16
Rhodium surface siloxide complexes were prepared directly by condensation of the molecular precursors ([{Rh(μ-OSiMe3)(cod)}2], [{Rh(μ-OSiMe3)(tfb)}2], [{Rh(μ-OSiMe3)(nbd)}2]) with silanol groups on silica surface (Aerosil 200 and SBA-15) and their structures were characterized by 13C and 29Si CP/MAS NMR spectroscopy. Such single-site complexes were tested for their activity in hydrosilylation of carbon–carbon double bonds with triethoxysilane, heptamethyltrisiloxane and poly(hydro,methyl)(dimethyl)siloxane. The best catalyst appeared to be cyclooctadiene ligand-containing rhodium siloxide complex immobilized on Aerosil which was recycled as many as 20 times without loss of activity and selectivity in hydrosilylation of vinylheptamethyltrisiloxane with heptamethyltrisiloxane. On the ground of CP/MAS NMR measurements it was established that the mechanism of hydrosilylation catalyzed by silica-supported rhodium siloxide complexes is different from that for the complexes in the homogeneous system. 相似文献
13.
Isabel Castellote 《Tetrahedron letters》2004,45(4):769-772
The first intermolecular C-N bond-forming reactions between substituted 2-bromopyrroles and primary and cyclic secondary amines were performed using Pd2(dba)3 as catalyst with BINAP as the ligand. The aminations proceeded in the presence of NaOtBu at 80-100 °C in 31-93% yields. 相似文献
14.
《Journal of organometallic chemistry》1992,429(3):C46-C48
A palladium catalyst generated from Pd2(dba)3·CHCl3 and nBu2PCH2CH2Py (Py = 2-pyridyl) has effected novel cycloaddition of methoxyallene with CO2 to afford (E)-5-methoxy-2-(methoxy-methylene)-4-methylene-5-pentanolide regio- and stereospecifically, where a methoxy functional group plays an important role. 相似文献
15.
Dr. Noel Nebra Sonia Ladeira Prof. Laurent Maron Prof. Blanca Martin‐Vaca Dr. Didier Bourissou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8474-8481
In the course of our investigations on polymetallic complexes derived from 1,3‐bis(thiophosphinoyl)indene (Ind(Ph2P?S)2), we observed original fluxional behavior and report herein a joint experimental/computational study of this dynamic process. Starting from the indenylidene chloropalladate species [Pd{Ind(Ph2P?S)2}Cl]? ( 1 ), the new PdII???RhI hetero‐bimetallic pincer complex [PdCl{Ind(Ph2P?S)2}Rh(nbd)] ( 2 ; nbd=2,5‐norbornadiene) was prepared. X‐ray crystallography and DFT calculations substantiate the presence of a d8???d8 interaction. According to multinuclear variable‐temperature NMR spectroscopic experiments, the pendant {Rh(nbd)} fragment of 2 readily shifts in solution at room temperature between the two edges of the SCS tridentate ligand. To assess the role of the pincer‐based polymetallic structure on this fluxional behavior, the related monometallic Rh complex [Rh{IndH(Ph2P?S)2}(nbd)] ( 3 ) was prepared. No evidence for a metal shift was observed in that case, even at high temperature, thus indicating that inplane pincer coordination to the Pd center plays a crucial role. The previously described PdII???IrI bimetallic complex 4 exhibited fluxional behavior in solution, but with a significantly higher activation barrier than 2 . This finding demonstrates the generality of this metal‐shift process and the strong influence of the involved metal centers on the associated activation barrier. DFT calculations were performed to shed light onto the mechanism of such metal‐shift processes and to identify the factors that influence the associated activation barriers. Significantly different pathways were found for bimetallic complexes 2 and 4 on one hand and the monometallic complex 3 on the other hand. The corresponding activation barriers predicted computationally are in very good agreement with the experimental observations. 相似文献
16.
Reaction of vinylcyclopropanes having two electron-withdrawing groups with α,β-unsaturated esters or ketones in the presence of Pd2(dba)3.CHC13-1,2- bis(diphenylphosphino)ethane (dppe) or tributylphosphine catalyst gave vinyl- cyclopentanes in good yields. 相似文献
17.
A.S. Berenblyum A.G. Knizhnik S.L. Mund I.I. Moiseev 《Journal of organometallic chemistry》1982,234(2):219-235
The interaction of Ph3PPD(OAc)22 with molecular H2 yields a binuclear complex of zero-valent palladium, (Ph3P)2Pd2. This complex interacts reversibly with H2 in CH2Cl2, yielding (Ph3P)2Pd2H2. In argon atmosphere (Ph3P)2Pd2 reacts with [Ph3PPd(OAc)22 to form a binuclear complex of PdI with a metal—metal bond. These data, as well as the results of kinetic studies of the reactions between [Ph3PPd(OAc)22 and H2, are in agreement with an autocatalytic mechanism for the process, including catalysis of the reduction of PdII complexes by the Pd0 compounds. It has been established that the synthesized compound of PdII, PdI and Pd0 with the ratio P/Pd?1, are inactive in the hydrogenation of unsaturated compounds. The catalytically active complex (PPh)2Pd5 is formed when palladium acetate reacts with (Ph3P)2Pd2 in the presence of H2. The same compound is formed when a solution of (Ph3P)2Pd2 is treated with a mixture of H2 and O2 (or H2O2 in an atmosphere of H2). (PPh)2Pd5 is an effective catalyst for the hydrogenation of olefins, dienes, acetylenes, aldehydes, organic peroxides, quinones, O2, Schiff bases, and nitro, nitroso, and azo compounds. 相似文献
18.
[Pd4(3-CR)(-Cl)3(PBu
3
1
)4] (R = H, F) have been synthesized from [Pd2(dba)3]. PBu
3
1
and CRCl3 and characterized spectroscopically and in one case by a single crystal X-ray crystallographic analysis, These compounds undergo substitution reactions with LiBr and tertiary phosphines and are catalyst for the polymerization of ethyne. Details of these reactions are discussed for the compound [ Pd4(3-CR)(-Cl)3(PBu
3
1
)4]. The cluster lbrmation reactions. have been monitored using31P(1H)NMR studies. 相似文献
19.
Elizaveta P. Shestakova Viktor N. Khrustalev 《Journal of organometallic chemistry》2007,692(20):4297-4302
Treating the complexes [Rh(TFA)(PPh3)2], [Rh(HFA)(PPh3)2], and [Rh(TFA)(Cod)] (TFA - trifluoroacetylacetonate, HFA - hexafluoroacetylacetonate, Cod - 1,5 cyclooctadiene) with an excess of NaBPh4 in acetonitrile yields the rhodium(I) complexes with coordinated [BPh4]− anion, [Rh(PPh3)2(π-PhBPh3)] · 2MeCN (I) and [Rh(Cod)(π-PhBPh3)] (II). The reactions present a new example of β-diketonate ligand replacement. The 1H, 31P, and 11B NMR spectra of I and II are discussed. [Rh(PPh3)2(π-PhBPh3)] has been characterized by single crystal X-ray analysis. 相似文献
20.
Several methods for the synthesis of the Pd38(CO)28L12 cluster (L = PEt3) by treatment of Pd10(CO)12L6 with CF3COOH-Me3NO, CF3COOH-H2O2, Pd(OAc)2-Me3NO, and Pd2(dba)3 mixtures (dba is dibenzylideneacetone) were proposed. The tri-n-butylphosphine analog, Pd38(CO)28(PBu3)12, was synthesized by the reaction of Pd10(CO)14(PBu3)4 with Me3NO. The reaction of Pd4(CO)5L4 with Pd2(dba)3 yields clusters with an icosahedral packing of the metal atoms, Pd34(CO)24L12 and Pd16(CO)13L9.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 167–170, January, 1995. 相似文献