A new palladium-catalyzed coupling reaction of vinylic and allylic triflates with pyrimidine nucleosides

1991 ◽  
Vol 69 (2) ◽  
pp. 198-200 ◽  
Author(s):  
Mohamed Ezeldin Hassan
Keyword(s):  
Key Words ◽  
Palladium Catalysis ◽  
Coupling Reaction ◽  
Pyrimidine Nucleosides ◽  
Mild Conditions ◽  
Palladium Catalyzed ◽  
High Yields

Vinylic trifluoromethane sulfonates (triflates) form palladium intermediates that react with pyrimidine nucleosides to produce C-5 alkyl substituted nucleosides after hydrogenation of the vinylic coupling products with hydrogen and Pd/C in methanol. The reaction, which is run under mild conditions, appears to be a general one since both mono- and disubstituted vinylic triflates, as well as the cyclic ones, gave high yields of the corresponding C-5 alkyl-substituted nucleoside. The reaction with allyl triflate requires the use of the 5-chloromercurinucleoside. Key words: nucleosides, triflates, palladium catalysis

Palladium-catalyzed Suzuki cross-couplings of N′-mesyl arylhydrazines via C–N bond cleavage

RSC Advances ◽  
2014 ◽  
Vol 4 (49) ◽  
pp. 25576-25579 ◽  
Author(s):  
He-Ping Zhou ◽  
Jin-Biao Liu ◽  
Jian-Jun Yuan ◽  
Yi-Yuan Peng
Keyword(s):  
Boronic Acid ◽  
Bond Cleavage ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Mild Conditions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
High Yields ◽  
Aryl Boronic Acid ◽  
Biaryl Compounds

An efficient palladium-catalyzed Suzuki cross-coupling reaction of N′-mesyl arylhydrazine with aryl boronic acid is described, which affords the corresponding biaryl compounds in high yields. This transformation proceeds through C–N bond cleavage under mild conditions.

Ferromagnetic Chain Based on Verdazyl-Nitroxide Diradical

2020 ◽  
Author(s):  
Evgeny Tretyakov ◽  
Svetlana Zhivetyeva ◽  
Pavel Petunin ◽  
Dmitry Gorbunov ◽  
Nina Gritsan ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Ferromagnetic Coupling ◽  
Nitronyl Nitroxide ◽  
Triplet Ground State ◽  
One Dimensional ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Ferromagnetic Chain ◽  
High Yields

<p>Verdazyl-nitroxide diradicals were synthesized using the palladium-catalyzed cross-coupling reaction of the corresponding iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields (up to 82%). The synthesized diradicals were found to be highly thermally stable and have a singlet (D<i>E</i><sub>ST</sub> » -64 cm<sup>–1</sup>) or triplet ground state (D<i>E</i><sub>ST</sub> ³ 25 and 100 cm<sup>–1</sup>), depending on which canonical hydrocarbon diradical type they belong to. Upon crystallization, triplet diradicals form unique one-dimensional (1D) spin <i>S</i> = 1 chains of organic diradicals with intrachain ferromagnetic coupling of <i>J</i>′/<i>k</i><sub>B</sub> from 3 to 6 K.</p>

Palladium Catalyzed Synthesis of Phenylquinoxaline-Alkyne Derivatives via Sonogashira Cross Coupling Reaction

2021 ◽  
Vol 43 (1) ◽  
pp. 95-95
Author(s):  
Rifhat Bibi Rifhat Bibi ◽  
Muhammad Yaseen Muhammad Yaseen ◽  
Haseen Ahmad Haseen Ahmad ◽  
Ismat Ullah Khan Ismat Ullah Khan ◽  
Shaista Parveen Shaista Parveen ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Sonogashira Reaction ◽  
Terminal Alkynes ◽  
Vinyl Halides ◽  
Sonogashira Coupling Reaction ◽  
Quinoxaline Derivatives ◽  
Palladium Catalyzed ◽  
High Yields ◽  
Alkyne Derivatives

Transition metals mediated cross coupling methodologies provide an extremely powerful versatile pathway in organic syntheses undoubtedly, a facile route for syntheses and derivatization of biologically important heterocycles from easily available precursors. Sonogashira coupling reaction, a leading method to Csp-Csp2 bond formation is one of the most important and rapid pathways to couple aryl/vinyl halides with terminal alkynes. Current research study deals with the synthesis of alkyne substituted quinoxaline derivatives. The quinoxalines class of aromatic heterocycles exhibits a wide variety of important biological potencies. Palladium catalyzed cross coupling process provided an effective synthetic practice for the synthesis of alkyne derivatives of quinoxaline. Vareity of terminal alkynes were coupled with 2-(4-bromophenyl)quinoxaline under optimized conditions for Sonogashira reaction, affording alkyne substituted quinoxaline derivatives in high yields. The optimized reaction conditions for coupling of range of terminal alkyne with quinoxaline basic core render this process significant for designing of medicinally interesting precursors.

Regiospecific Palladium-Catalyzed Cross-Coupling Reactions Using the Operational Equivalent of 1,3-Dilithiopropyne

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jorge A. Cabezas ◽  
Natasha Ferllini
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkyne ◽  
Copper Iodide ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
High Yields

A regiospecific palladium-catalyzed cross-coupling reaction using the operational equivalent of the dianion 1,3-dilithiopropyne, with aromatic iodides is reported. This reaction gives high yields of 1-propyn-1-yl-benzenes and 2-(propyn-1-yl)thiophenes in the presence of catalytic amounts of palladium(0) or (II) and stoichiometric amounts of copper iodide. No terminal alkyne or allene isomers were detected. Reaction conditions were very mild and several functional groups were tolerated.

scholarly journals A facile preparation of 4-aryl-3-[(tert-butyldimethylsilyl)oxymethyl]furans

1991 ◽  
Vol 69 (8) ◽  
pp. 1326-1330 ◽  
Author(s):  
Brian A. Keay ◽  
Jean-Louis J. Bontront
Keyword(s):  
Key Words ◽  
Coupling Reaction ◽  
Aryl Bromides ◽  
Palladium Catalyzed ◽  
Facile Preparation

A series of aryl bromides undergo a palladium-catalyzed coupling reaction with 3-[(tert-butyldimethylsilyl)oxymethyl]-4-(tri-n-butylstannyl)furan to provide 4-aryl-3-[(tert-butyldimethylsilyl)oxymethyl]furans in moderate to good yields. Key words: palladium, cross-couplings, stannanes, 3,4-disubstituted furans.

Coordination Effect Enabled Palladium-Catalyzed Regioselective O-Alkylation of 2-Pyridones

2022 ◽  
Author(s):  
Zhiqiang Lu ◽  
yanzhi li ◽  
yi ru ◽  
shujian yang ◽  
chu hao ◽  
...  
Keyword(s):  
Pyridine Ring ◽  
Palladium Catalysis ◽  
Palladium Catalyzed ◽  
Coordination Effect ◽  
High Yields

A novel tactic for regioselective O-alkylation of 2-pyridones has been realized through palladium catalysis in moderate to high yields. The coordination effect between palladium and nitrogen on pyridine ring plays...

Coupling reaction of Aryl Halides Promoted by NiCl2/PPh3/Sm0

2002 ◽  
Vol 2002 (11) ◽  
pp. 562-563 ◽  
Author(s):  
Xingliang Zheng ◽  
Yongmin Zhang
Keyword(s):  
Functional Groups ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Efficient Synthesis ◽  
Mild Conditions ◽  
Coupling Reagent ◽  
High Yields

An efficient synthesis of biaryls from various aryl halides has been developed and investigated. The coupling reagent is a catalytic mixture of anhydrous NiCl2 and PPh3 in the presence of metallic samarium. The reaction occurs rapidly under mild conditions, tolerates a variety of functional groups with high yields.

scholarly journals Mechanistic investigations of bipyrimidine-promoted palladium-catalyzed allylic acetoxylation of olefins

2009 ◽  
Vol 87 (1) ◽  
pp. 264-271 ◽  
Author(s):  
Bo-Lin Lin ◽  
Jay A Labinger ◽  
John E Bercaw
Keyword(s):  
Acetic Acid ◽  
Key Words ◽  
Palladium Catalysis ◽  
Allylic Oxidation ◽  
Competition Experiment ◽  
Catalyst Precursor ◽  
Mechanistic Studies ◽  
Allyl Acetate ◽  
Palladium Catalyzed ◽  
Terminal Olefins

Several pyridine-like ligands were found to improve Pd(OAc)2-catalyzed allylic oxidation of allylbenzene to cinnamyl acetate by p-benzoquinone in acetic acid. The best ligand examined, bipyrimidine, was used to identify the catalyst precursor for this system, (bipyrimidine)Pd(OAc)2, which was fully characterized. Mechanistic studies suggest the reaction takes place through disproportionation of (bipyrimidine)Pd(OAc)2 to form a bipyrimidine-bridged dimer, which reacts with olefin to form a PdII-olefin adduct, followed by allylic C–H activation to produce (η3-allyl)PdII species. The (η3-allyl)PdII intermediate undergoes a reversible acetate attack to generate a Pd0-(allyl acetate) adduct, which subsequently reacts with p-benzoquinone to release allyl acetate and regenerate (bipyrimidine)Pd(OAc)2. No KIE is observed for the competition experiment between allylbenzene-d0 and allylbenzene-d5 (CD2=CDCD2C6H5), suggesting that allylic C–H activation is not rate-determining. Catalytic allylic acetoxylations of other terminal olefins as well as cyclohexene were also effected by (bipyrimidine)Pd(OAc)2.Key words: olefin, palladium catalysis, allylic C–H oxidation, p-benzoquinone, bipyrimidine.

ChemInform Abstract: High Yields of Symmetrical Biaryls from Palladium-Catalyzed Homocoupling of Arylboronic Acids Under Mild Conditions.

ChemInform ◽  
2010 ◽  
Vol 28 (23) ◽  
pp. no-no
Author(s):  
K. A. SMITH ◽  
E. M. CAMPI ◽  
W. R. JACKSON ◽  
S. MARCUCCIO ◽  
C. G. M. NAESLUND ◽  
...  
Keyword(s):  
Arylboronic Acids ◽  
Mild Conditions ◽  
Palladium Catalyzed ◽  
High Yields

scholarly journals Bipyridylacetylenes 1: the synthesis of some bipyridylacetylenes via the palladium-catalyzed coupling of acetylenes with 2,2′-dibromobipyridyl, and the single crystal X-ray structure of 6,6′-bisphenylethynyl-2,2′-bipyridine

1991 ◽  
Vol 69 (7) ◽  
pp. 1117-1123 ◽  
Author(s):  
Ian R. Butler ◽  
Chantal Soucy-Breau
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Key Words ◽  
Dihedral Angle ◽  
Palladium Catalysis ◽  
Crystal Data ◽  
X Ray ◽  
Acetylenic Bond ◽  
Palladium Catalyzed

The synthesis of a series of 6,6′-diethynyl-2,2′-bipyridyls from the palladium-catalyzed coupling of 6,6′-dibromo-2,2′-bipyridine with a series of arylacetylenes is reported. The single crystal X-ray structure of 6,6′-phenylethynyl-2,2′-bipyridyl was determined. Crystal data: monoclinic, A2/a, with cell constants a = 10.0385(4), b = 9.2166(4), c = 21.4130(8) Å, and β = 102.981(3)°; Dcalc. = 1.226 g cm−3, Z = 4, Rf = 0.045, S = 1.22, using 886 reflections of the 1443 unique reflections. The packing diagram indicates essentially that the molecules pack in a layered assembly with the nitrogen atoms of the dipyridyl groups on opposite sides and with a dihedral angle of 59.85(16)° between the pyridyl and phenyl groups. The acetylenic bond distances are normal. Key words: acetylene, palladium, catalysis, coupling, monomers, crystal structure.

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