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1.
[formula: see text] Alkyl-substituted chromium Fischer carbene complexes were found to react with various N-tosylimines to give beta-methoxy allylic amine derivatives under thermal conditions. This result is essentially distinct from the photochemical outcome in which beta-lactam derivatives are obtained. 相似文献
2.
José G. López-Cortés Luis F. Contreras de la Cruz Ruben A. Toscano Henri Rudler 《Journal of organometallic chemistry》2005,690(9):2229-2237
Ferrocenyllithium reacts with M(CO)6 (M = Cr, W, Mo) in THF to give, after alkylation at oxygen, the corresponding carbene complexes 3a-c in good yield. Complexes 3a,b were characterized by X-ray analysis. These complexes react with pentylamine to give the corresponding aminocarbene complexes 7a-c and with allylamine to give, in the case of chromium and tungsten, the corresponding and expected aminonocarbene complexes 8a,b, and for molybdenum, complex 9c in which the double bond is already coordinated to the metal. 8a,b could be converted in 9a,b in excellent yield. The structure of 9a could be confirmed by an X-ray analysis. Alkylations at nitrogen could be carried on complex 9c as well as on complexes 9a,b. 相似文献
3.
Yu. E. Begantsova L. N. Bochkarev Yu. P. Barinova G. V. Basova N. E. Stolyarova I. K. Grigor’eva I. P. Malysheva G. K. Fukin E. V. Baranov Yu. A. Kurskii G. A. Abakumov 《Russian Chemical Bulletin》2007,56(2):255-260
The molybdenum silicon-containing carbene complexes PhMe2Si—CH=Mo(NAr)(OR)2 (1), Ph2Si[CH=Mo(NAr)(OR)2]2 (2), and (RO)2(ArN)Mo=CH—(SiMe2)2—CH=Mo(NAr)(OR)2 (Ar = 2,6-Pri
2C6H3; R = CMe2CF3) were synthesized by the reaction of the R′— CH=Mo(NAr)(OR)2 compounds (R′ = But or PhMe2C) with silicon-containing vinyl reagents. The structures of complexes 1 and 2 and the known PhMe2C—CH=Mo(NAr)(OCMe2CF3)2 compound were established by X-ray diffraction. The catalytic properties of the silicon-containing carbene complexes in homometathesis
of hex-1-ene and metathesis polymerization of cyclooctene were studied. The catalytic activity of these complexes and the
stereoregularity of the resulting polyoctenamers substantially depend on the nature of the substituent at the carbene carbon
atom.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 247–252, February, 2007. 相似文献
4.
Synthetic utility of the Fischer-type carbene complexes of chromium for the preparation of nitrogen-containing compounds is demonstrated. Alkoxy carbene complexes reacted with imines to give (optically active) 3-pyrrolines and beta-methoxy allylic amine derivatives in good yields. The amino carbene complexes reacted with alpha,beta-unsaturated aldehydes to give substituted pyrroles in good yields. 相似文献
5.
6.
《Tetrahedron letters》1986,27(49):5915-5918
Reactions of phenyl morpholino or pyrrolidino chromium carbene complexes with alkynes in DMF at 120–125°C resulted in exclusive formation of the indene derivatives. 相似文献
7.
8.
N-alkylaminocarbene complexes of chromium were found to react with alpha,beta-unsaturated aldehydes to give pyrroles in good yields. 相似文献
9.
The low-temperature reaction of [CrCl3(thf)3] with LiC6H3Cl2-2,6 yields the organochromium(III) compound [Li(thf)4][CrIII(C6H3Cl2-2,6)4] (1) in 48% yield. The homoleptic, anionic species [CrIII(C6H3Cl2-2,6)4]− is electrochemically related to the neutral one [CrIV(C6H3Cl2-2,6)4] (2) through a reversible one-electron exchange process (E1/2 = 0.16 V, ΔEp = 0.09 V, ipa/ipc = 1.18). Compound 2 was isolated in 74% yield by chemical oxidation of 1 with [N(C6H4Br-4)3][SbCl6]. Attempts to prepare the salt [NBu4][CrIII(C6Cl5)4] (4) by direct arylation of [CrCl3(thf)3] with LiC6Cl5 in the presence of [NBu4]Br gave the organochromium(II) salt [NBu4]2[CrII(C6Cl5)4] (3) instead, as the result of a reduction process. The salt [NBu4][CrIII(C6Cl5)4] (4) was cleanly prepared by comproportionation of 3 and [CrIV(C6Cl5)4]. The reaction of [MoCl4(dme)] with LiC6Cl5 in Et2O solution proceeded with oxidation of the metal center to give the paramagnetic (S = 1/2), five-coordinate salt [Li(thf)4][MoVO(C6Cl5)4] (5). The crystal and molecular structures of 1 and 2 have been established by X-ray diffraction methods. The magnetic properties of 1 and 4 (S = 3/2) as well as those of 2 (S = 1) have been established by EPR spectroscopy as well as by ac and dc magnetization measurements. 相似文献
10.
Seongjin Kim Young Tak Lee Helmut Sitzmann 《Journal of organometallic chemistry》2007,692(24):5390-5394
Chromium Fischer carbene complexes, [Cr{OMe(R)}(CO)5] have been utilized as a source of chromium carbonyls in the synthesis of chromium NHC complexes. Using the synthetic method, chromium complexes of various NHC ligands were isolated in reasonable yields. Moreover, the method can be employed for the synthesis of molybdenum and tungsten NHC compounds. 相似文献
11.
Summary The interconversion of carbyne, carbyne and hydride complexes derived from protonations oftrans-[M(CNMe)2(dppe)2](M = Mo or W) has been studied. The initial site of protonation is shown to be the isonitrile nitrogen and all protonations proceed through the common carbyne intermediatetrans-[M(CNHMe)(CNMe)(dppe)2]+. The CNHMe group in traps-[M(CNHMe)2(dppe)2]2+ is shown to be susceptible to electrophilic attack at N and nucleophilic attack at ligating C, the new complexestrans-[W(CNH2Me)(CNHMe)(dppe)2](BF4)3 andtrans-[Mo(CHNHMe)(CNHMe)(dppe)2]BF4 being formed, respectively. 相似文献
12.
Bishnu Dhakal Lalith S.R. Gamage Yanshi Zhang James W. Herndon 《Tetrahedron letters》2017,58(14):1403-1407
Three-component coupling of Fischer carbene complexes, enyne aldehyde hydrazones, and electron-deficient alkynes leads to simple benzoate derivatives in a process involving the formation of an N-aminopyrrole derivative, Diels-Alder reaction, and nitrene extrusion. The products are readily converted into isoquinolones through reaction with primary amines. The reaction proceeds best with highly substituted and electron-rich pyrroles even though these are the sterically least favorable substrates, and this reactivity trend is supported by a computational study. 相似文献
13.
Organocatalytic enantioselective Friedel-Crafts reaction of pyrrole derivatives with imines 总被引:2,自引:0,他引:2
A highly enantioselective Friedel-Crafts reaction of pyrrole derivatives with N-acyl imines catalyzed by chiral phosphoric acids was developed. The reactions produced the pyrrole derivatives in high yields and enantioselectivity. 相似文献
14.
Praetorius JM Allen DP Wang R Webb JD Grein F Kennepohl P Crudden CM 《Journal of the American Chemical Society》2008,130(12):3724-3725
The reaction of oxygen with rhodium complexes containing N-heterocyclic carbenes was found to give dioxygen complexes with rare square planar geometries and unusually short O-O bond lengths. Analysis of the bonding in these complexes by Rh L-edge X-ray absorption spectroscopy (XAS), Raman spectroscopy, and DFT calculations provides evidence for a bonding model in which singlet oxygen is bound to a Rh(I) d8 metal complex, rather than the more common Rh(III) d6 peroxo species with octahedral geometry and O-O bond lengths in the 1.4-1.5 A range. 相似文献
15.
Reactions of a pyrrole- and a phenyl-carbene chromium complexes with 3-alkoxy-1-ethoxy-1-butyne produced dimers through o-quinone-methide formation from the alkyne-carbene cycloaddition products and subsequent Diels-Alder dimerization. 相似文献
16.
The Ugi three-component reaction with 2-substituted five-, six-, and seven-membered cyclic imines was investigated. The reaction opens a new route to substituted proline and homoproline derivatives. It was shown that the method is efficient for the one-step preparation of seminatural dipeptides containing natural amino acid residues, and fragments of substituted proline or pipecolinic acid. The scope and limitation of the approach are discussed. 相似文献
17.
Thermal decomposition of the 2H‐azaphosphirene metal complexes 1a–c in the presence of 1‐piperidinecarbonitrile and heterocumulene derivatives 3, 4 , and 5 yielded the Δ3‐1,3,2‐oxazaphospholene complexes 6c and the Δ3‐1,3,2‐thiazaphospholene complexes 7a–c as isolable products; the latter represent the first complexes of this ring system. It is remarkable that these trapping reactions of the nitrilium phosphanylide complexes 2a–c , which were formed as reactive intermediates, proceeded with high regio‐ and substrate selectivities. The complexes were isolated by column chromatography and characterized by elemental analysis, NMR spectroscopy and mass spectrometry. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:72–76, 2002; DOI 10.1002/hc.1108 相似文献
18.
Charles P. Casey Loren D. Albin Marian C. Saeman Dennis H. Evans 《Journal of organometallic chemistry》1978,155(2):C37-C40
The reduction of a series of (arylmethoxycarbene)pentacarbonyltunsten(0) compounds was studied by cyclic voltammetry and a dependence of E of the quasi-reversible voltammogram on the conformation of the aryl ring of the carbene complex was observed. 相似文献
19.
The reaction of propargylsilanes with Fischer carbene complexes has been examined. If the silane-containing carbon is secondary the predominant pathway involves formation of conjugated dienes through a 1,2-silicon shift process of the initially formed vinylcarbene complex intermediate. If a primary propargylsilane is employed, the silicon does not shift and normal alkyne-Fischer carbene coupling processes are observed. The process is moderately stereoselective, resulting in the E enol ether and Z alkenylsilane. 相似文献