scholarly journals The Phospha–Michael addition product {(t-BuNH)P(μ-N-t-Bu)2P(=N-t-Bu)—C(=CH2)CH(p-CH3O—C6H4)-P(O)[(OCH2C(CH3)2CH2O)]}

2011 ◽  
Vol 67 (5) ◽  
pp. o1212-o1213
Author(s):  
G. Gangadhararao ◽  
Srinivas Venu
Keyword(s):  
Michael Addition ◽  
Addition Product

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.

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.

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

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.

Carcinogenicity of lactones. V. The reactions of 4-hydroxypent-2-enoic acid lactone with α-toluenethiol, benzylamine, methylamine, imidazole, and guanidine

1970 ◽  
Vol 48 (10) ◽  
pp. 1574-1578 ◽  
Author(s):  
J. Bryan Jones ◽  
Jill N. Barker
Keyword(s):  
Michael Addition ◽  
Ring Opening ◽  
Lactone Ring ◽  
Addition Product ◽  
Enoic Acid ◽  
Michael Additions ◽  
Ring Opening Reactions ◽  
Acid Lactone ◽  
Ph Range ◽  
The Michael Addition

The Michael additions of α-toluenethiol, methylamine, and benzylamine to 4-hydroxypent-2-enoic acid lactone have been confirmed to be facile. The analogous additions of imidazole and glycine amide are much less readily accomplished and no stable Michael addition product could be detected with guanidine as the base. In the pH range 6–9, subsequent lactone ring opening reactions of the Michael addition products were observed only when methylamine (pKa 9.3) and benzylamine (pKa 10.6) were used as nucleophiles.

The reactivity of 3-Ethenyl-4-methylcyclohex-2-en-1-one and related compounds towards some carbanionic nucleophiles

1984 ◽  
Vol 37 (11) ◽  
pp. 2305 ◽  
Author(s):  
RFC Brown ◽  
GL Burge ◽  
DJ Collins
Keyword(s):  
Silica Gel ◽  
Lewis Acid ◽  
Michael Addition ◽  
Acid Catalysis ◽  
Main Product ◽  
Addition Product ◽  
Butyl Alcohol ◽  
Similar Reaction ◽  
Keto Ester ◽  
Related Compounds

The reaction of 3-ethenyl-4-methylcyclohex-2-en-1-one (4) with 2-methylcyclopentane-1,3-dione in refluxing toluene containing pyridine gave 6% of 9bξ-hydroxy-3a,6-dimethyl-3a,4,5,6,7,9b-hexahydro-1H-benz[e]indene-3,9(2H,8H)-dione (10). When the same reactants were heated at 100-110� (sealed tube) in benzene containing t-butyl alcohol and diethylamine the main product (61%) was 5',6-dimethylspiro[bicyclo[3.2.1]octane-1,2'-cyclohexane]-3,6',8'-trione (11); the yield of (11) was 72% when the reaction was carried out in the presence of silica gel. Attempts to effect a similar reaction of the dienone (4) with methyl 1β-t-butoxy-7aβ-methyl-5-oxo-1,2,3,3aα,4β,6,7,7a-octahydro-indene-4-carboxylate (21a) gave no conjugate Michael addition product, but (21a) underwent aminolysis to the corresponding diethylamide (21b). Attempts to alkylate the t-butoxy β-keto ester (21a) under various conditions with 7-acetyloxy-7-ethenyl-8 ξ methyl-1,4-dioxaspiro[4,5]decane (41) failed. Similarly, attempts to effect alkylation of the anion of the t-butoxy keto ester (21a) with 7-ethenyl-8-methyl-1,4-dioxaspiro[4,5]dec-6-ene (43) under Lewis acid catalysis were also unsuccessful.

5-Fluorouracil (5-FU)-based Aza-Michael addition product: A selective carbonic anhydrase IX inhibitor

2021 ◽  
Vol 1231 ◽  
pp. 129977
Author(s):  
Md Mushtaque ◽  
Fernando Avecilla ◽  
Irfan Ahmad ◽  
Ahmed M. Alharbi ◽  
Parvez Khan ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Michael Addition ◽  
Addition Product ◽  
Carbonic Anhydrase Ix
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