ChemInform Abstract: NUCLEOPHILIC ADDITION TO ACTIVATED OLEFINS. 3. REACTIONS OF PIPERIDINE AND MORPHOLINE WITH BENZYLIDENEMALONONITRILE IN 50% DIMETHYL SULFOXIDE-50% WATER. INTRINSIC BARRIERS IN NUCLEOPHILIC ADDITIONS

1980 ◽  
Vol 11 (29) ◽  
Author(s):  
C. F. BERNASCONI ◽  
J. P. FOX ◽  
S. FORNARINI
Keyword(s):  
Dimethyl Sulfoxide ◽  
Nucleophilic Addition ◽  
Nucleophilic Additions ◽  
Activated Olefins

Formation of spiro adduct from N-methyl-N-(2,4,6-trinitrophenyl)glycine anion

1989 ◽  
Vol 54 (2) ◽  
pp. 440-445 ◽  
Author(s):  
Vladimír Macháček ◽  
Alexandr Čegan ◽  
Miloš Sedlák ◽  
Vojeslav Štěrba
Keyword(s):  
Nmr Spectroscopy ◽  
Dimethyl Sulfoxide ◽  
Equilibrium Constant ◽  
Mole Fraction ◽  
Nucleophilic Addition ◽  
Adduct Formation ◽  
First Case ◽  
C Nmr

The intramolecular nucleophilic addition of N-methyl-N-(2,4,6-trinitrophenyl)glycine anion in methanol-dimethyl sulfoxide mixtures produces spiro[(3-methyl-5-oxazolidinone)-2,1'-(2',4',6'-trinitrobenzenide)]. The spiro adduct has been identified by means of 1H and 13C NMR spectroscopy. This is the first case when the formation of a Meisenheimer adduct with carboxylate ion is observed. Logarithm of the equilibrium constant of adduct formation increases linearly with the mole fraction of dimethyl sulfoxide in its mixture with methanol.

Superelectrophilicity in Michael-Type Reactions: Water Addition to 4-Nitrobenzodifuroxan

Synthesis ◽  
2017 ◽  
Vol 49 (15) ◽  
pp. 3453-3459 ◽  
Author(s):  
Sami Lakhdar ◽  
Guillaume Berionni ◽  
François Terrier
Keyword(s):  
Aqueous Solution ◽  
Nucleophilic Additions ◽  
Water Addition ◽  
Meldrum’S Acid ◽  
Thermodynamic Measurements ◽  
Michael Acceptors ◽  
Activated Olefins ◽  
Ph Range ◽  
Electrophilic Character ◽  
Complexation Process

Kinetic and thermodynamic measurements of the ease of covalent hydration of 4-nitrobenzodifuroxan (NBDF) to give the corresponding hydroxy adduct has been carried out over a large pH range of 0.82–12.23 in aqueous solution. A most important result is that water is the sole efficient nucleophile contributing to the hydration of this peculiar nitroolefin in the pH range 4–8. Based on this finding as well as a pK a H2O value of 2.85 for the complexation process there is no doubt that the electrophilic character of NBDF falls in the domain of superelectrophilicity defined with reference to covalent nucleophilic additions to 4,6-dinitrobenzofuroxan (DNBF; pK a H2O = 3.75) and related heterocycles. This also corresponds to a positioning of NBDF at the top of the electrophilicity scale E introduced by Mayr to describe the feasibility of nucleophilic-electrophilic combinations. Returning to the hydration of the series of activated olefins, it has been possible to expand the domain of reactivity of Michael acceptors by six orders of magnitude, going from benzylidenemalonitrile (pK a H2O = 10.70; E = –9.42) to the para-nitro-substituted benzylidene Meldrum’ s acid (pK a H2O = 3.46; E = –5.49). The positioning of these olefins on the pK a scale shows that not only 4-nitrobenzodifuroxan but also the unsubstituted Meldrum’s acid are located in the superelectrophilic region.

scholarly journals Tales of the Unexpected: Selectivity of Nucleophilic Additions to Zigzag Nanographene Diones

2020 ◽  
Author(s):  
Peter Ribar ◽  
Leos Valenta ◽  
Tomas Solomek ◽  
Michal Juricek
Keyword(s):  
Late Stage ◽  
Nucleophilic Addition ◽  
Model Systems ◽  
Nucleophilic Additions

Nucleophilic addition of carbon-centered nucleophiles to nanographene ketones represents a valuable late-stage method for the functionalization of zigzag nanographenes, but its use is rare in the chemical literature. Using two model systems, non-Kekulé triangulene-4,8-dione and Kekulé anthanthrone, we identify unexpected regioselectivities and uncover the rules that govern these reactions. Considering the large number of nanographene ketones that have been reported since the pioneering work of Eric Clar, this method enables synthesis and exploration of hitherto unknown functionalized nanographenes.

scholarly journals Tales of the Unexpected: Selectivity of Nucleophilic Additions to Zigzag Nanographene Diones

2020 ◽  
Author(s):  
Peter Ribar ◽  
Leos Valenta ◽  
Tomas Solomek ◽  
Michal Juricek
Keyword(s):  
Late Stage ◽  
Nucleophilic Addition ◽  
Model Systems ◽  
Nucleophilic Additions

Nucleophilic addition of carbon-centered nucleophiles to nanographene ketones represents a valuable late-stage method for the functionalization of zigzag nanographenes, but its use is rare in the chemical literature. Using two model systems, non-Kekulé triangulene-4,8-dione and Kekulé anthanthrone, we identify unexpected regioselectivities and uncover the rules that govern these reactions. Considering the large number of nanographene ketones that have been reported since the pioneering work of Eric Clar, this method enables synthesis and exploration of hitherto unknown functionalized nanographenes.

Nitrosodicyanomethanide Complexes of Cu(II) and Co(II) with Methylpyrazoles; Nucleophilic Additions and Coligand Isomers

1994 ◽  
Vol 59 (12) ◽  
pp. 2611-2620 ◽  
Author(s):  
Mária Hvastijová ◽  
Jiří Kohout ◽  
Darina Kováčová ◽  
Renate Skirl
Keyword(s):  
Thermal Decomposition ◽  
Coordination Sphere ◽  
Nucleophilic Addition ◽  
Esr Spectroscopy ◽  
Central Atom ◽  
Electronic Spectroscopy ◽  
Nucleophilic Additions ◽  
Chelate Ligands ◽  
L Systems ◽  
New Compounds

From the M(II) ONC(CN)2--L systems, where M = Cu or Co and L = pyrazole (pz), 3(5)-methylpyrazole (mpz), 3,4,5-trimethylpyrazole (tmpz), or indazole (inz), the following new compounds were prepared: [M{ONC(CN)2}2L4] with M = Cu, L = pz; M = Co, L = pz, mpz, inz; [M{ONC(CN)2}2L2] with M = Cu, L = tmpz, inz; M = Co, L = tmpz; [M{L.ONC(CN)2}2] with M = Cu, L = mpz; M = Co, L = tmpz. All compounds were studied by thermal decomposition and by infrared and electronic spectroscopy, the Cu(II) complexes also by ESR spectroscopy. Six-coordinate octahedral or pseudooctahedral structures were assigned to complexes of all the types. Nitrosodicyanomethanide is nitroso-N-bonded and in the [M{OCN(CN)2}2L2] complexes is involved in the bidentate bridging. The [M{L.ONC(CN)2}2] complexes contain anionic chelate ligands formed by nucleophilic addition of the N(imine)-C(cyano) type in the M(II) coordination sphere. The first coligand isomer pair with Co(II) central atom is presented.

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