29945-53-7Relevant academic research and scientific papers
C-H arylation and alkenylation of imidazoles by nickel catalysis: Solvent-accelerated imidazole C-H activation
Muto, Kei,Hatakeyama, Taito,Yamaguchi, Junichiro,Itami, Kenichiro
, p. 6792 - 6798 (2015/11/24)
The first nickel-catalyzed C-H arylations and alkenylations of imidazoles with phenol and enol derivatives are described. Under the influence of Ni(OTf)2/dcype/K3PO4 (dcype: 1,2-bis(dicyclohexylphosphino)ethane) in t-amyl alcohol, imidazoles can undergo C-H arylation with phenol derivatives. The C-H arylation of imidazoles with chloroarenes as well as that of thiazoles and oxazoles with phenol derivatives can also be achieved with this catalytic system. By changing the ligand to dcypt (3,4-bis(dicyclohexylphosphino)thiophene), enol derivatives could also be employed as coupling partners achieving the C-H alkenylation of imidazoles as well as thiazoles and oxazoles. Thus, a range of C2-arylated and alkenylated azoles can be synthesized using this newly developed nickel-based catalytic system. The key to the success of the C-H coupling of imidazoles is the use of a tertiary alcohol as solvent. This also allows the use of an air-stable nickel(ii) salt as the catalyst precursor.
General method for functionalized polyaryl synthesis via aryne intermediates
Truong, Thanh,Mesgar, Milad,Le, Ky Khac Anh,Daugulis, Olafs
supporting information, p. 8568 - 8576 (2014/07/07)
A method for base-promoted arylation of arenes and heterocycles by aryl halides and aryl triflates is described. Additionally, in situ electrophilic trapping of ArLi intermediates generated in the reaction of benzyne with deprotonated arenes or heterocycles has been developed, providing rapid and easy access to a wide range of highly functionalized polyaryls. Base-promoted arylation methodology complements transition-metal-catalyzed direct arylation and allows access to structures that are not easily accessible via other direct arylation methods. The reactions are highly functional-group tolerant, with alkene, ether, dimethylamino, trifluoromethyl, ester, cyano, halide, hydroxyl, and silyl functionalities compatible with reaction conditions.
C-H bonds as ubiquitous functionality: Preparation of multiple regioisomers of arylated 1,2,4-triazoles via C-H arylation
Joo, Jung Min,Guo, Pengfei,Sames, Dalibor
, p. 738 - 743 (2013/02/25)
We describe a general approach for the synthesis of complex aryl 1,2,4-triazoles. The electronic character of the C-H bonds and the triazole ring allows for the regioselective C-H arylation of 1-alkyl- and 4-alkyltriazoles under catalytic conditions. We have also developed the SEM and THP switch as well as trans-N-alkylation, which enable sequential arylation of the triazole ring to prepare 3,5-diaryltriazoles. This new strategy provides rapid access to a variety of arylated 1,2,4-triazoles and well complements existing cyclization methods.
COPPER-CATALYZED C-H BOND ARYLATION
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Page/Page column 17; 22, (2009/04/24)
The present invention is a one-step method for efficiently converting carbon-hydrogen bonds into carbon-carbon bonds using a combination of aryl halides, a substrate, and a copper salt as catalyst. This method allows faster introduction of complex molecular entities, a process that would otherwise require many more steps. This invention is particularly relevant for the organic synthesis of complex molecules such as, but not limited to, pharmacophores and explosives.
A general method for copper-catalyzed arylation of arene C-H bonds
Do, Hien-Quang,Khan, Rana M. Kashif,Daugulis, Olafs
supporting information; experimental part, p. 15185 - 15192 (2009/03/12)
A general method for copper-catalyzed arylation of sp2 C-H bonds with pKa's below 35 has been developed. The method employs aryl halide as the coupling partner, lithium alkoxide or K3PO4 base, and DMF, DMPU, or mixed DMF/xylenes solvent. A variety of electron-rich and electron-poor heterocycles such as azoles, caffeine, thiophenes, benzofuran, pyridine oxides, pyridazine, and pyrimidine can be arylated. Furthermore, electron-poor arenes possessing at least two electron-withdrawing groups on a benzene ring can also be arylated. Two arylcopper-phenanthroline complex intermediates were independently synthesized.
Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate): an efficient catalyst for regioselective C-2 arylation of heterocycles
Nandurkar, Nitin S.,Bhanushali, Mayur J.,Bhor, Malhari D.,Bhanage, Bhalchandra M.
, p. 1045 - 1048 (2008/09/17)
Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate), a structurally well defined O-containing transition metal complex is reported as an efficient catalyst for regioselective direct C-2 arylation of heterocycles with aryl halides. The present protocol is applicable to a wide variety of heterocycles providing good to excellent yields of products.
Copper-catalyzed arylation of heterocycle C-H bonds
Do, Hien-Quang,Daugulis, Olafs
, p. 12404 - 12405 (2008/09/17)
A new method for the direct, copper-catalyzed arylation of heterocycle C-H bonds by aryl halides has been developed. In addition to electron-rich five-membered heterocycles, electron-poor pyridine oxides can also be arylated. The best results are obtained by using a combination of lithium tert-butoxide base, aryl iodide coupling partner, and copper iodide catalyst. Copyright
Synthesis of 1,2,4-Triazines, IX. Synthesis of Cyclopenta-1,2,4-triazines
Metz, Hans-Joachim,Neunhoeffer, Hans
, p. 2807 - 2818 (2007/10/02)
Derivatives 12a - f and 23a - c of hitherto unknown cyclopenta-1,2,4-triazine system 1 were prepared from cyclopentadienedicarboxylates 9a,b and amidrazones 10a - d or 14a - c, respectively.
