Syntheses of C-nucleosides. IX. Reactions of D,L-3,4-di-O-isopropylidene-2,5-anhydroallose with Wittig reagents. Syntheses of bis-homo anhydro-C-nucleosides.

1976 ◽  
Vol 54 (18) ◽  
pp. 2940-2947 ◽  
Author(s):  
George Just ◽  
Mohabir Ramjeesingh ◽  
Teng Jiam Liak
Keyword(s):  
Michael Addition ◽  
Nmr Spectra ◽  
Addition Product

The nmr spectra of the two anomers of 1-O-acetyl-3,4-di-O-isopropylidene-2,5-anhydro-D,L-allose (2a, 2b) are discussed. The reactions of D,L-3,4-di-O-isopropylidene-2,5-anhydroallose (1) with carbethoxymethylenetriphenylphosphorane, bromocarbethoxymethylenetriphenylphosphorane and ethyl triphenylphosphoranylidene pyruvate to give respectively the olefin derivatives 7, 9, and 10 and an internal Michael addition product 11 are described. From 11, two bis-homo anhydro-C-nucleosides having 6-azauracil (15) and 4-hydroxy-5-carbox-amidopyrazole (19) bases were synthesized.

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.

Study of the Reactivity of 2-Benzylidene[3]ferrocenophane-1,3-dione with Ethyl Acetoacetate and Some Other C-Nucleophiles

1993 ◽  
Vol 58 (9) ◽  
pp. 2128-2138
Author(s):  
Marta Sališová ◽  
Ľubomír Šebo ◽  
Štefan Toma ◽  
Eva Solčániová
Keyword(s):  
Intramolecular Cyclization ◽  
Michael Addition ◽  
Ethyl Acetoacetate ◽  
Nmr Spectra ◽  
H Nmr ◽  
Michael Adducts ◽  
Pyran Derivative ◽  
Dihydropyridine Derivatives ◽  
Sole Product

Michael addition of C-nucleophiles to 2-benzylidine[3]ferrocenophane-1,3-dione has been studied. In some cases, (ethyl acetoacetate, acetylacetone and malononitrile as the C-nucleophiles) the addition was followed by intramolecular cyclization leading to pyran derivatives. Addition of malononitrile gave the pyran derivative as a sole product. The Michael adducts of ethyl acetoacetate and acetylacetone can be converted to [7]ferrocenophane-1,7-dione derivatives by refluxing in benzene with triethylamine as catalyst. they also easily react with ammonia, under SiO2 catalysis, to give Hantzsch dihydropyridine derivatives. The 1H NMR spectra of the products are discussed.

The Thomson Synthesis of (–)-GB17

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Michael Addition ◽  
Physiological Activity ◽  
Addition Product ◽  
Systematic Investigation ◽  
Unsaturated Ester ◽  
Wide Range ◽  
Stereogenic Centers ◽  
Northwestern University ◽  
Convergent Assembly ◽  
Stereogenic Center

(–)-GB17 3 is one of the Galbulimima alkaloids, a family that shows a wide range of interesting physiological activity. Regan J. Thomson of Northwestern University devised (Angew. Chem. Int. Ed. 2012, 51, 2481) a convergent assembly of 3, a key step of which was the intramolecular Michael cyclization of 1 to 2. The hydroxy aldehyde 6 was prepared by alkylation of the dithiane 4 with 5, followed by hydrolysis. The preparation of 9, by condensation of 8 with 7 followed by hydrogenation and protection, had been reported by Lhommet. Condensation of 9 with the linchpin reagent 10 gave an intermediate keto phosphonate, which was combined with 6 to give, after oxidation, the aldehyde 1. Two new stereogenic centers are created in the course of the cyclization of 1. The authors found that the TFA salt 11 of the Hayashi catalyst delivered 2 with high diastereocontrol. Control experiments showed that the buttressing effect of the dithiane was required for the cyclization. The authors then explored the next intramolecular Michael cyclization of 13 to 14. In this cyclization, the stereogenic center at 6 is in jeopardy by elimination and readdition. Cyclization of the trans unsaturated ester led to the wrong diastereomer of 14, but cyclization of the cis ester 13, prepared by the Still-Gennari protocol, cleanly gave the desired diastereomer. The reaction worked best with the free amine. Under the conditions of the reaction the Michael addition product spontaneously cyclized to the lactam 14. The ketone of 14 was selectively enolized, then converted to its enol triflate, which under Pd-mediated reduction gave the alkene 15. Alkylation of 15 with 16 predominantly gave the diene 18. Hydrolysis of the dithiane to the ketone followed by reduction gave mainly the desired equatorial alcohol, which was cleaved oxidatively to (–)-GB17 3. Although there have been many isolated reports of the utility of intramolecular Michael addition as a synthetic method, there has been little systematic investigation. The optimization studies that are the heart of this work are a welcome addition.

Coordination compounds of indium. Part 44. The oxidation of indium(I) halides by tetrahalogeno-ortho-quinones

1988 ◽  
Vol 66 (11) ◽  
pp. 2935-2940 ◽  
Author(s):  
Theodore A. Annan ◽  
Dennis G. Tuck
Keyword(s):  
Coordination Compounds ◽  
Nmr Spectra ◽  
Dynamic Behaviour ◽  
Addition Product ◽  
Donor Ligands ◽  
Chelate Complexes ◽  
H Nmr ◽  
Anionic Complexes ◽  
Derivatives Of ◽  
C Nmr

The reaction of indium(I) halides (InX; X = Cl, Br, I) with tetrahalogeno-ortho-quinones (Y4C6O2; Y = Cl, Br) gives the oxidative addition product Y4C6O2InX, These compounds have been isolated as adducts with neutral bidentate donor ligands (N,N,N′,N′-tetramethylethanediamine (tmen), 1,10-phenanthroline) or as salts of the anionic complexes [Y4C6O2InCl2]− or [Y4C6O2In(Cl)Br]−. The number of coordinated tmen molecules, and hence the structure, depends on the method of preparation. Infrared, 1H NMR, and 13C NMR spectroscopy all confirm that these products are all substituted-catecholato derivatives of indium(III), and the structure of these various neutral or anionic derivatives is discussed. The temperature dependence of the 13C NMR spectra shows that the dynamic behaviour of these compounds (in d6-dmso) is similar to that observed in previous studies of indium(III) chelate complexes.

ChemInform Abstract: Unexpected Regiospecific Michael Addition Product: Synthesis of 5,6-Dihydrobenzo[1,7]phenanthrolines.

ChemInform ◽  
2015 ◽  
Vol 46 (36) ◽  
pp. no-no
Author(s):  
Selvaraj Mohana Roopan ◽  
Annadurai Bharathi ◽  
Jeyakannu Palaniraja ◽  
K. Anand ◽  
R. M. Gengan
Keyword(s):  
Michael Addition ◽  
Addition Product

Synthesis of ATRP macroinitiator based on synthetic cis- 1,4-polyisoprene and its application for graft polymerization of MMA

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Lapporn Vayachuta ◽  
Pranee Phinyocheep ◽  
Daniel Derouet ◽  
Sagrario Pascual
Keyword(s):  
Chemical Reaction ◽  
Nmr Spectra ◽  
Graft Polymerization ◽  
Addition Product ◽  
Epoxide Ring ◽  
Order Kinetic ◽  
First Order ◽  
Molecular Weights ◽  
H Nmr ◽  
Methylpropionic Acid

AbstractModification of synthetic cis-1,4-polyisoprene (PI) into bromoalkylfunctionalized polyisoprene (PIBr), an ATRP macroinitiator, was investigated by two-step chemical reaction. The PI was partially epoxidized into epoxidized polyisoprene (EPI) using m-chloroperbenzoic acid, then the EPI was transformed into PIBr by reaction with 2-bromo-2-methylpropionic acid. The results from 1H NMR revealed that the addition product occurs in competition with epoxide ring rearrangement. The amount of bromoalkyl functionalized units was determined from 1H NMR spectra. The graft polymerization of MMA using ATRP technique from macroinitiator units in PIBr was investigated using three different ligands, i.e. N-(n-octyl)-2-pyridylmethanimine (NOPMI), N-(n-octadecyl)-2-pyridylmethanimine (NODPMI) and 1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA), resulting in formation of graft copolymer of PI and PMMA. The PMMA grafts were successfully separated from the PI backbone using acidolysis for studying their number-average molecular weights (M̄̅̅n,SEC ) and polydispersity indexes (PDI). All of the ligands used give a increase of M̄̅̅n with MMA conversion. Comparing between 3 ligands, Cu(I)Br complexed with NOPMI shows first-order kinetic plot.

Absolute Konfiguration von (+)-1,2,3,4,6,7,8,8a-Octahydro-6-isochinolon- 8a-carbonsäuremethylester und die Stereochemie einer Kupfer-katalysierten asymmetrischen Michael-Reaktion / Absolute Configuration of Methyl (+)-1,2,3,4,6,7,8,8a-Octahydro-6-isoquinolone-8a-carboxylate and Stereochemistry of a Copper-Catalyzed Asymmetric Michael Reaction

2004 ◽  
Vol 59 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Jens Christoffers ◽  
Wolfgang Frey ◽  
Heiko Scharl ◽  
Angelika Baro
Keyword(s):  
Absolute Configuration ◽  
Michael Addition ◽  
Michael Reaction ◽  
Addition Product ◽  
Crystallographic Analysis ◽  
Subsequent Reaction ◽  
X Ray ◽  
Quaternary Stereocenter ◽  
Asymmetric Michael Reaction

AbstractEnantiopure Boc-protected piperidine derivative (+)-5c, with a quaternary stereocenter, was obtained by copper-catalyzed, L-valine diethylamide-mediated Michael reaction. For determination of the absolute configuration, 5c was derivatized by cyclization with pyrrolidine/AcOH to give compound 6 with bicyclo[4.4.0]-constitution, deprotection of the amino function with TFA and subsequent reaction with 2-iodobenzoic acid to yield the crystalline bicyclic amide 7. X-ray crystallographic analysis confirmed the constitution of compounds 5c and 6 and established the (R) configuration of 7. Thus, starting Michael addition product (+)-5c has to be (S) configured, because an epimerization at the quaternary stereocenter is excluded. This result is in accordance with our working model of the Cu-catalyzed, auxiliary-assisted Michael reaction.

Unexpected regiospecific Michael addition product: synthesis of 5,6-dihydrobenzo[1,7]phenanthrolines

RSC Advances ◽  
2015 ◽  
Vol 5 (48) ◽  
pp. 38640-38645 ◽  
Author(s):  
Selvaraj Mohana Roopan ◽  
Annadurai Bharathi ◽  
Jeyakannu Palaniraja ◽  
K. Anand ◽  
R. M. Gengan
Keyword(s):  
Michael Addition ◽  
Addition Product ◽  
Unexpected Formation ◽  
First Time

The unexpected formation of 5,6-dihydrobenzo[1,7]phenanthroline instead of 5,6-dihydrobenzo[1,7]phenanthroline-3-carbonitrile in acridine molecules using Michael addition has been observed for the first time.

The synthesis of 1,4-diketones

1976 ◽  
Vol 29 (2) ◽  
pp. 339 ◽  
Author(s):  
S Nimgirawath ◽  
E Ritchie ◽  
WC Taylor
Keyword(s):  
Michael Addition ◽  
Addition Product ◽  
Phenacyl Bromide ◽  
Unsaturated Ketone ◽  
Lower Yield ◽  
Derivatives Of ◽  
Acyl Derivatives ◽  
Moderate Yield

Recent methods for the synthesis of 1,4-diketones are briefly reviewed.Zinc and phenacyl bromide in dimethoxyethane afforded 1,4-diphenylbutane-l,4-dione in moderate yield, but other solvents or metals examined gave no or a lower yield. The route is unsatisfactoryfor aliphatic 1,4-diketones. Attempts to use 'levulinyl chloride' to acylate olefins or acetylenes were fruitless. Routes involving aldol condensations of hexane-2,5-dione or its monoacetal had very restricted success, as did those depending on the halogenolysis of acyl derivatives of phenacylmalonic ester. A fairly general route to 1,4-diketones was found in the sequence: valine to N-acylvaline to oxazol-5-one to Michael addition product with an α, β-unsaturated ketone followed by alkaline hydrolysis.The Michael addition is not regiospecific and valine derivatives may also be isolated. Yields of 1,4-diketones are only moderate but the synthesis is quick and convenient.

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