On the Stereoselectivity of the (-)-Dimenthyl Malonate Addition to α,β-Unsaturated Ketones

1996 ◽  
Vol 61 (12) ◽  
pp. 1805-1814 ◽  
Author(s):  
Ľubomír Šebo ◽  
Juraj Alföldi ◽  
Grety Rihs ◽  
Štefan Toma
Keyword(s):  
Michael Addition ◽  
Pure State ◽  
Nmr Spectra ◽  
Reaction Products ◽  
X Ray ◽  
Unsaturated Ketones ◽  
H Nmr ◽  
The Michael Addition

The Michael addition of (-)-dimenthyl malonate to eight α,β-unsaturated ketones has been studied. The ratio of diastereomers was calculated on the basis of the 1H NMR spectra of the crude reaction products. The diastereomer excess varied from 10 to 50%, depending on the structure of the starting enone. The pure diastereomer produced by addition of (-)-dimenthyl malonate to 2-benzylidene-1,4-indandione was isolated by repeated crystallization. X-ray analysis has shown that the isomer is (-)-dimenthyl (R)-2-[1-(1,3-dioxoindan-2-yl)-1-phenylmethyl]malonate (5a). The predominating diastereomers of (-)-dimenthyl(3-ferrocenyl-3-oxophenylpropyl)malonate (1a) and (-)-dimenthyl-2-(1-(1,3-dioxo[3]ferrocenophan-2-yl)-1-phenyl malonate (6a) were also isolated in pure state by careful crystallization.

Photoreaktionen von Dekacarbonyldirhenium mit Allen und unverzweigten Allenderivaten / Photoreactions of Decacarbonyldirhenium with Allene and Unbranched Derivatives of Allene

1995 ◽  
Vol 50 (4) ◽  
pp. 649-660 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Wolfgang Michels ◽  
Gerhard Heeb
Keyword(s):  
Nmr Spectra ◽  
Crystal And Molecular Structure ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Oxidative Rearrangement ◽  
Dirhenium Complexes ◽  
Derivatives Of ◽  
By Products

Decacarbonyldirhenium (1) reacts upon UV irradiation with allene (2), 1,2-butadiene (3) and 2,3-pentadiene (4) preferentially by CO substitution and oxidative rearrangement to the corresponding enneacarbonyl-μ-η1:3-endiyl-dirhenium complexes 5, 9, and 15 and to the octacarbonyl-μ-η2:2-allene-dirhenium complexes 6, the stereoisomers 10, 11, and 16. At elevated temperature 5, 9, and 15 loose CO and yield by a reductive rearrangement also the complexes 6, 10, 11, and 16. In addition to these main products, depending upon the allene derivative used, various by-products are obtained.By-products of the reaction o f 1 with 2 are octacarbonyl-μ-η3:3-(2,3-dimethylene-buta-1,4- diyl)dirhenium (7) and μ-η2:2-allene-hexacarbonyl-μ-η1:3-1-propene-1,3-diyl-dirheniurn (8). The photo reaction of 1 with 3 yields, in addition to 9-11, tetracarbonyl-η3-(E-5-ethylidene- 4-methyl-2-cyclopenten-1-yl)rhenium (12) and tetracarbonyl-η3-(Z-5-ethyliden-4- methyl-2-cyclopenten-1-yl)rhenium (13) as a mixture of isomers. 1 and 4 form the by-products tetracarbonyl-η3-(EZ-3-penten-2-yl)rhenium (17), tetracarbonyl-η3-(EE-3-penten-2-yl)rhenium (18) and heptacarbonyl-μ-η1:2:1:2-(4,5-dimethyl-2,6-octadiene-3,6-diyl)dirhenium (19) with an unusually bridging and chelating ligand. The constitutions of the reaction products have been concluded from the IR and 1H NMR spectra. For 19 the crystal and molecular structure has been determined by X-ray diffraction analysis.

Reaktionsprodukte yon Oxylsäuremethylester-N-methylamiden mit Antimon(V)-chlorid. Molekülspektren und Struktur / Reaction Products of Oxalic Acid Methylester-N-methylamides and Antimony(V) Chloride. Molecular Spectra and Structure

1979 ◽  
Vol 34 (3) ◽  
pp. 398-405 ◽  
Author(s):  
M. Rössler ◽  
W. Schwarz ◽  
A. Schmidt
Keyword(s):  
Molecular Structure ◽  
Oxalic Acid ◽  
Nmr Spectra ◽  
Crystal And Molecular Structure ◽  
Molecular Spectra ◽  
Reaction Products ◽  
Addition Compound ◽  
Ring Systems ◽  
X Ray ◽  
H Nmr

Abstract Oxalic acid dimethylester and the oxalic acid methylester-N-methylamides 2 and 4, resp., react with antimony(V) chloride to yield the 1 : 1 addition compound 5 or the cyclic tetrachloroantimony(V) compounds 1, 3 and 6, resp., which represent SbO2C2 and SbONC2 five ring systems, resp. Li oxalic acid methylester-N-methylimide (9) and anti-mony(V) chloride gives the bicyclic octachloro-N-methylamido oxalato-O,O′-O,N-diantimony(V) (10). The crystal and molecular structure of tetrachloro-N-methylamino oxalato-O,O′-antimony(V) (3) is determined by X-ray analysis. The vibrational and 1H NMR spectra of 2-10 are reported and discussed.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

A 15N, 13C, and 1H NMR study of reaction products from arylguanidines and chloroformate esters

1991 ◽  
Vol 56 (7) ◽  
pp. 1505-1511 ◽  
Author(s):  
Antonín Lyčka ◽  
Karel Palát
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Reaction Products ◽  
H Nmr ◽  
Nmr Study

The 15N, 13C, and 1H NMR spectra of the reaction products from arylguanidines with two mols of chloroformate esters have been measured. With application of the corresponding 15N isotopomer it has been proved that the reaction products have the structures IIIa-IIIc.

Organometallic oxides: preparation of the cluster [(η-C5Me5)Mo]4O7 by reduction of [(η-C5Me5)MoCl(O)]2(μ-O) or (η-C5Me5)MoCl2(O)

2000 ◽  
Vol 78 (3) ◽  
pp. 383-394
Author(s):  
Frank Bottomley ◽  
Victor Sanchez ◽  
Robert C Thompson ◽  
Olusola O Womiloju ◽  
Zhiqiang Xu
Keyword(s):  
Nmr Spectra ◽  
Chloroform Solution ◽  
X Ray Diffraction ◽  
Broad Resonance ◽  
Nmr Spectrum ◽  
X Ray ◽  
Temperature Range ◽  
H Nmr ◽  
Tributyltin Hydride ◽  
Effective Moment

Reduction of [(η-C5Me5)MoCl(O)]2(μ-O) or (η-C5Me5)MoCl2(O) with sodium or magnesium amalgam, magnesium turnings, or tributyltin hydride produced [(η-C5Me5)Mo]4O7, with [(η-C5Me5)Mo(O)(μ-O)]2 as a co-product. [(η-C5Me5)Mo]4O7 was characterized by X-ray diffraction, mass spectrometry, 1H NMR and IR spectroscopies, and magnetism. Crystals of [(η-C5Me5)Mo]4O7 contained a tetrahedral [(η-C5Me5)Mo]4 unit (Mo-Mo = 2.909 (3) Å) with the Mo4O7 core having the structure Mo4(μ2-O(b))3(µ2-O(c))3(µ3-O(a)) (3). Microcrystalline samples of [(η-C5Me5)Mo]4O7 were paramagnetic over the temperature range 2-300 K, with an effective moment of 1.26 μB at 300 K. [(η-C5Me5)Mo]4O7 was also paramagnetic in chloroform solution, over the temperature range 223-298 K, with an effective moment of 1.43 µB at 298 K. The 1H NMR spectrum showed a broad resonance at 16.3 ppm (Δν 1/2 = 113 Hz) and two narrow resonances at 1.89 ppm and 1.69 ppm (Δν 1/2 = 5 Hz). The magnetism and NMR spectra showed that [(η-C5Me5)Mo]4O7 existed in two forms which were in equilibrium in solution. One form was paramagnetic (S = 1), with the Mo4O7 core having the geometry 3, and the other was diamagnetic (S = 0), with the Mo4O7 core having the geometry 4.Key words: cluster, cyclopentadienyl, molybdenum, oxide, paramagnetism.

scholarly journals Darstellung und Charakterisiening der Spezies R-C7H7Mo(CO)3 und die Röntgenstrukturanalyse von / Synthesis and Characterisation of the Species R-C7H7Mo(CO)3 and the X-ray Structure Determination of

1978 ◽  
Vol 33 (4) ◽  
pp. 361-365 ◽  
Author(s):  
Margret Sommer ◽  
Klaus Weidenhammer ◽  
Henning Wienand ◽  
Manfred L. Ziegler
Keyword(s):  
Carbon Atom ◽  
Structure Determination ◽  
Nmr Spectra ◽  
X Ray ◽  
Ethyl Group ◽  
H Nmr

The species R−C7H7Mo(CO)3 (R=−CH2COCH3,−CH(CH3)COCH3,−CH(CH)(CH3)2COCH3) have been synthesized by electrolysing [η7-C7H7Mo(CO)3]+, η7-C7H7Mo(CO)2Br and the dimers [C7H7Mo(CO)3]2 and (C7H7)2Mo(CO)3, respectively, in suitable ketones and HBr. 1H NMR spectra and the X-ray structure determination of (CH3−CO−CH(CH3)−C7H7)Mo(CO)3 revealed the CH3−CO−CH(CH3)-group being bonded to the cycloheptatriene ligand via the α-carbon atom of the ethyl group.

Zinc Complexes of Dimethyl(phthalimidomethyl)phosphine Oxide

1994 ◽  
Vol 49 (2) ◽  
pp. 258-262
Author(s):  
Sabi Varbanov ◽  
Elena Russeva ◽  
Andrei Ganchev
Keyword(s):  
Oxygen Atom ◽  
Phosphine Oxide ◽  
Nmr Spectra ◽  
Zinc Complexes ◽  
X Ray ◽  
H Nmr ◽  
Infrared Spectral ◽  
Phosphoryl Oxygen ◽  
Halide Complexes ◽  
Powder Analysis

A series o f zinc complexes of dimethyl(phthalimidomethyl)phosphine oxide (DPPO, L) have been synthesized: ZnX2L2, where X = Cl, Br, I or NO3. The complexes are characterized by elemental analysis, infrared and 1H NMR spectra and X-ray powder analysis. Infrared spectral data show that L is coordinated to zinc via the phosphoryl oxygen atom. The zinc halide complexes are found to be isostructural, while the pattern o f Zn(NO3)2L2 differs considerably from those o f halide complexes.

scholarly journals Addition of some 6-amino-4-aryl-2(1H)-pyridones to phenylisocyanate and related reactions

2019 ◽  
Vol 74 (2) ◽  
pp. 191-195
Author(s):  
Lyubomir Dimitrov Raev ◽  
Ivo Christov Ivanov ◽  
Silviya Georgieva Agontseva
Keyword(s):  
Michael Addition ◽  
Acetyl Derivative ◽  
Phenyl Isocyanate ◽  
Crystallographic Analysis ◽  
Molar Ratio ◽  
X Ray ◽  
The Michael Addition

AbstractThe Michael addition of enaminoesters to coumarins leads to the formation of the rearranged adduct 1 whose structure has been previously elucidated by X-ray crystallographic analysis. Now, N- and/or O-carbamoylation of the 6-amino-2-pyridone 1 by treatment with phenyl isocyanate in a molar ratio of 1:1 and 1:2 gave N-mono- (2a) or N,O-bis-(phenylcarbamoyl) (3) derivatives, respectively. Further transformations of the corresponding new 2-pyridone derivative 2a into the O-acetyl derivative 2b and the chromeno[3,4-c]pyridine 4 are reported as well.

scholarly journals Atran-analoge Verbindungen des Typs / Atrane Analogous Compounds of the Type

1984 ◽  
Vol 39 (3) ◽  
pp. 341-351 ◽  
Author(s):  
Joseph Grobe ◽  
Gerald Henkel ◽  
Bernt Krebs ◽  
Nikolaos Voulgarakis
Keyword(s):  
Structure Analysis ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Trigonal Bipyramid ◽  
Angular Distortion ◽  
Type I ◽  
Tetrahedral Coordination ◽  
Cage Compounds ◽  
X Ray ◽  
H Nmr

Heterocyclic cage compounds of type I (compounds 8-10) have been prepared by condensation reactions of 1,2,2-trifunctional disilanes Me(R)XSiSiMeX2 (R = Me, Ph, OEt; X = NMe2, OEt) with triethanolamine using the “Dilution Principle”. The starting compounds are obtained by Si-Me cleavage of Si2Me6 with acetylchloride/AlCl3 followed by either aminolysis with HNMe2 or alcoholysis with EtOH. 1H NMR spectra indicate N→Si(1) intraction with the more acidic Si atom in 8 and 9. This result is proved by the X-ray structure analysis of 8 (monoclinic, P21/c; a = 7,088(2), b = 15,070(4), c = 12,701(4) Å, β = 104,96(2) at -130 °C, Z = 4); the Si(1)···N distance is found to be 2,768 Å , connected with a significant angular distortion of the tetrahedral coordination around Si(1) towards a trigonal bipyramid. In compound 10, too, N→Si(1) coordination is observed at room temperature in spite of almost equal acidity for both Si atoms. This can be explained by the preference of 5- over 6-membered chelating ring systems. At higher temperatures the 1H NMR spectra show a fluctuation of the N-donor between the two Si centres.

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