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1.
Herein, the direct C-5 fluoroalkylselenolation of 8-aminoquinolines is described. The Pd-catalyzed reaction is performed with the in situ generated fluoroalkylselenyl chloride and various 8-aminoquinoline amides or sulfonamides. The desired products were formed in moderate to excellent yields.  相似文献   

2.
A rhodium-catalyzed ortho-CH functionalization and annulation between enaminones and sulfoxonium ylides was developed, affording a series of multi-substituted naphthalenes in good to moderate yields with excellent functional group compatibility. The procedure featured with enaminone acting as both a directing and cyclization bifunctional group, and the application of sulfoxonium ylide in CH functionalization.  相似文献   

3.
The formation of N-(2'-(diphenylphosphoryl)-[1,1′-biphenyl]-2-yl)-2,3,4,5,6-pentafluorobenzamide (3_eaaa) has been achieved through the palladium-catalyzed and Ag(I)-assisted CH functionalization of N-([1,1′-biphenyl]-2-yl)-2,3,4,5,6-pentafluorobenzamide (1_eaa) via phosphination and in the presence of diphenylphosphine oxide (2_a). The reaction was accompanied with small amount of carbazole derivative, (9H-carbazol-9-yl)(perfluorophenyl)methanone (4_eaa). Crystal structures of 3_eaaa and 4_eaa were both determined by X-ray crystal diffraction methods. Indeed, phosphination took place at the ortho-position of inter-annular ring of 1_eaa. Substituents with various electron-withdrawing/donating capacities on the amido-fragment of 1 were found to greatly affect the ratio distribution of products 3 and 4. By contrast, substituents on various locations of the biphenyl in 1 do not influence much on the outcome of the products distribution. A reaction mechanism is proposed to account for these experimental observations. Computational studies employing Density Functional Theory methods (DFT) on this proposed mechanism found that the electron density property of the palladium metal center in the intermediate II is critical to the formation of either 3 or 4. A relatively electron-poor palladium metal center favors the pathway of forming 3. On the contrary, the pathway of producing 4 will be prevailed while the palladium metal center is having fair amount of electron-density in the proposed intermediate II.  相似文献   

4.
The first methodology of CH arylation of heteroarene via 2D transition metal dichalcogenides that have catalytically active edge functional groups was described. The terminal sulfur groups could effectively catalyze a formation of an azo-linked intermediate with aryl diazonium salts, leading to produce heteroarenes with good yields. This novel methodology using bulk 2D transition metal dichalcogenides that have catalytically active edge functional groups can apply for various reactions to achieve CC bond formation in the fields of heterogeneous catalysis that is easily separable, highly reusable, and inexpensive method.  相似文献   

5.
The oxidative addition of phenolic electrophiles at Ni(0) in the presence of monodentate phosphine ligands was studied with both dispersion-free and dispersion-containing DFT methods. With the popular bulky ligand PCy3, consideration of dispersion has a striking effect on the predicted ligation state of nickel during oxidative addition of aryl sulfamates. Dispersion-containing methods such as M06L indicate a clear preference for a bis-phosphine ligated transition state (TS), while dispersion free methods like B3LYP strongly favor a mono-phosphine ligated TS. This discrepancy in predicted ligation state is also found with small phosphines (PMe3) in combination with some aryl electrophiles (carbamates, acetates, pivalates, chlorides), but a bis-PMe3-ligated TS is predicted regardless of dispersion for other electrophiles (sulfamates, mesylates, tosylates). DFT calculations that include dispersion also offer a possible explanation for the observed poor efficacy of PtBu3 as a ligand in Ni-catalyzed cross-coupling reactions.  相似文献   

6.
The difluoroalkylation of unactivated benzo[d]isoxazoles with ethyl difluorobromoacetate by visible-light photoredox catalysis via direct and regioselective CH functionalization has been efficiently achieved under mild reaction conditions. The difluoroalkylated adducts could be readily converted to a variety of corresponding CF2-containing heterocycles, demonstrating the synthetic utility of the present approach.  相似文献   

7.
Ordered deuterium arrangements and order-disorder transformations of the tantalum deuterides in the range TaD0.50TaD0.78 have been studied by neutron diffraction and calorimetry at temperatures between ?170 and 120°C. In addition to the disordered phase (α), three ordered phases based on the superstructures Ta2D1+x (β1), Ta4D3, (γ), and TaD (δ) are clarified. The Ta2D1+x structure is a nonstoichiometric from of the Ta2D superstructure over the rangex < 0.5. The γ-phase is formed below ?70°C near Ta4D3, and transforms into theβ1and δ-phases, respectively, in the hypo and hyperstoichiometric compositions. The δ-phase that exists beyond TaD0.75 changes to the disordered α-phase around 100°C.  相似文献   

8.
The phase relations in the system NiOTiO2 were studied between 1000 and 1600°C using quenched powder specimens, DTA runs, and single crystal diffusion couples. Quenching experiments establish the stable phases TiO2 (rutile), NiTiO3 an ilmenite structure type, Ni2(1+x)Ti1?xO4 (x ≥ 0.16), a cation-excess spinel, and Ni1?2xTixO (rocksalt structure type). DTA runs reveal the existence of an additional nonstoichiometric ilmenite phase Ni1?2xTi1+xO3 (x ≤ 0.03) above 1260°C. In quenched (1500, 1450°C) or slowly cooled single crystal diffusion couples, mutual oriented exsolutions occur in the rutile crystal and in the ilmenite diffusion zone. Orientation relations are: {101}rutile{1120}ilmenite; ∥010〉rutile∥00.1〉ilmenite. The cation-excess spinel decomposes below 1375°C into oriented intergrowth of NiTiO3 (ilmenite) and NiO: {111}NiO{0001}NiTiO3; ∥110〉NiO∥21.0〉NiTiO3.  相似文献   

9.
A new type of amido-oxazoline ligands was conveniently synthesized from inexpensive and commercially available materials in high yields and enantiomeric excesses. The corresponding chiral copper complexes with this class of ligands [C2 symmetric S,S-bis(amido-oxazoline-Cu(II) complex] were synthesized accordingly. The ORTEP diagram of ligand 6a and complex 6a-copper were compared and characterization of the complex confirmed the involvement of both dentate parts of the ligands, the oxygen and nitrogen atoms, in complexation with copper. The utilization of this amido-oxazoline ligands in the copper-catalyzed enantioselective esterification of allylic CH bonds of cyclic olefins with tert-butyl-4-nitrobenzoperoxoate resulted in the highest activities, yields (up to 95%) and enantioselectivities (up to 96%) in the presence of HZSM-5 zeolite. These new findings highlight the protocol as one of the most attractive and useful methods for the oxidation of the asymmetric allylic CH bond of cycloalkenes compared to other methodologies reported in the literature.  相似文献   

10.
11.
Rhodium(I)-catalyzed intermolecular cycloadditions of alkynes with vinyl aziridines bearing a conjugated carbonyl group in the olefin moiety followed by the double migration resulted in the formation of pyrrole derivatives in a one pot fashion.  相似文献   

12.
The crystal structure of bis(cyclopentadienyldicarbonyl-chromium) has been determined by x-ray diffraction. The compound crystalizes in the triclinic system, space group P1¯(C1i, No. 2) with unit cell parameters: a, 7.829(3); b, 14.543(6); c, 6.588(2)Å; α, 94.67(3), β, 110.70(3); γ, 104.04°(3); V, 699.1(4)Å3; z=2. There are two independent molecules per unit cell located at the inversion centers at O,O,O and O, 1/2, O. The CrCr bond distances are, respectively 2.200(3) and 2.230(3), thus supporting their formulation as triple bonds. The CpCrCr angles in the two molecules are 165.0° and 158.7°, respectively. The structural features are compared with those of Cp2Mo2(CO)4, which has a linear CpMoMoCp axis; and the differences rationalized in terms of electronic interactions of the Cp-ligand with the orbitals of the M2 unit. The differences observed in the structures of the two independent molecules are also related to the proposed bonding model and to packing considerations.  相似文献   

13.
Transition metal catalysis has enabled the highly stereoselective and protecting group-free synthesis of the C14C23 fragment of the apoptosis-inducing natural products biselyngbyolide A and B. A Pd-catalyzed Stille reaction between a vinyl stannane and a crotyl carbonate formed the skipped diene with complete control of the trisubstituted bond and excellent control over the branched/linear products. A Cu-catalyzed Stahl oxidation was used to form the requisite aldehyde needed for a Ag-catalyzed asymmetric allylation. The latter provided the final fragment with excellent stereochemical control.  相似文献   

14.
Tin(II) chloride inserts into the ironcarbon σ-bond in MeFe(CO)2Cp (Cp = cyclopentadienyl), in refluxing methanol or THF, to give MeClSnFe(CO)2- Cp and traces of Cl3SnFe(CO)2Cp, but, with EtFe(CO)2Cp, a mixture of the insertion product, Cl3SnFe(CO)2Cp, and Cl2Sn[Fe(CO)2Cp]2 is formed. Insertion of tin(II) chloride was not observed for MeMo(CO)3Cp and MeMn(CO)5; in these reactions, and in those between tin(II)_bromide and MeFe(CO)2Cp, EtFe(CO)2Cp and Memo(CO)3Cp, mixtures of halo—metal carbonyls and halotin—metal carbonyls result.  相似文献   

15.
16.
17.
Triazaphospholes react with 1,2-diketones to give spirocyclic phosphorus compounds by a 1.1 addition at phosphorus atom; with o-quinones one obtains spirobicyclic hexacoordinated phosphorus compounds. The reaction of 1,2-diketones with λ3-phosphazene oligomers appears different, to some extent, and can be used as a test for the existence of a monomer-oligomer equilibrium.  相似文献   

18.
The reactions of hexacarbonyl-molybdenum and -chromium with arylformamidines yield Mo2{HC(NR)2}4 and Cr2{HC(NR)2}4, respectively. In the case of Mo the reaction proceeds by the formation of pentacarbonyl formamidinemolybdenum and tetracarbonyldiformamidinemolybdenum complexes. Reaction of Mo2{HC(NR)2}4 with Mo(CO)6 yield the novel complexes Mo2{HC(NR)2}3-{HC(NR)NR · Mo(CO)3} and Mo2{HC(NR)2}2 {HC(NR)NR · Mo(CO)3}2, in which the [Mo(CO)3] moiety is bonded to one of the aromatic groups. In the case of chromium, only Cr2{HC(NR)2}3 {HC(NR)NR · Cr(CO)3¦ could be prepared. In solution, the formamidine complexes show monomer—dimer equilibria, which are strongly dependent on the nature of R. W(CO)6 reacts with formamidines, but did not yield complexes analogous to those for chromium and molybdenum. The properties of the new complexes are discussed.  相似文献   

19.
La phase α de type perovskiteBaFe1?xZnxO2,5?x/2 (0.05 < x < 0,40) pre´sente un ferrimagne´tisme faible pourx < 0,25, avecTc de l'ordre de 470°C, puis paramagne´tique (au-dessus de 77 K) pourx > 0,25, ce qui traduit la destruction progressive de l'ordre antiferromagne´tique observe´dans BaFeO2.5. Les phases β (Ba4Fe2Zn2O9) et γ (BaZn1?yFeyO2+y/2) sont en accord avec une forte perturbation du site octae´drique de la perovskite. La conductivite´est asseze´leve´e, de caracte`re mixte, avec une re´partition ionique-e´lectronique qui de´pend des conditions de synthe`se, et de la tempe´rature compte tenu dese´nergies d'activation diffe´rentes. Le coefficient de diffusion de l'oxyge`ne qui s'en de´duit este´leve´, mais le nombre de porteurs est restreint par la formation de paires de lacunes d'oxyge`ne tendant vers la coordinence 4 du fer.  相似文献   

20.
A metal-free iodine/TBHP-mediated oxidative CN bond formation for the one-pot synthesis of N-fused 1,2,4-triazoles and related heterocycles via cyclization has been developed. This reaction which is amenable to scale-up affords the corresponding products with good to excellent yields and tolerates a wide range of functional groups.  相似文献   

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