- Direct access to pentenedinitriles: Via Ni-catalyzed dihydrocyanation of 1,3-enynes
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A highly regio-and stereoselective dihydrocyanation of 1,3-enynes was implemented by nickel/diphosphine catalysts. This reaction represents the first example of Ni-catalyzed dihydrocyanation of 1,3-enynes using TMSCN and MeOH as HCN surrogates. In this tr
- Fang, Xianjie,Gao, Jihui,Sun, Feilong
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- Pd(II)-Catalyzed C3-Selective Arylation of Pyridine with (Hetero)arenes
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Palladium catalyzed, nondirected C3-selective arylation of pyridines with arenes and heteroarenes in the presence of 1,10-phenanthroline as the ligand has been developed. The optimized conditions allow for a highly C3-selective arylation of pyridines, affording various 3,3′-bipyridines and 3-arylpyridines. (Chemical Equation Presented).
- Gao, Guo-Lin,Xia, Wujiong,Jain, Pankaj,Yu, Jin-Quan
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supporting information
p. 744 - 747
(2016/03/01)
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- Palladium-catalyzed cyclization of vinyl iodide-tethered allensulfonamide
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This Letter describes a palladium-catalyzed cyclization of vinyl iodide-tethered allensulfonamide in the presence of alkylol, which provides a facile access to 2-alkoxy-3-methylene-tetrahydropyridine. The asymmetric version of this reaction has also been preliminarily realized with up to 81% enantioselectivity when chiral bisphosphine ligands were used.
- Xie, Zheng,Wu, Pan,Cai, Liangzhen,Tong, Xiaofeng
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p. 2160 - 2162
(2014/04/03)
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- AMVN-initiated expedient synthesis of biaryls by the coupling reaction of unactivated arenes and heteroarenes with aryl iodides
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The role of radical initiators AMVN and AIBN has been studied in the potassium tert-butoxide mediated biaryl coupling reaction of aryl iodides with unactivated arenes. Radical initiator AMVN promoted carbon-carbon bond formation expeditiously from aryl iodide having various groups such as amino, methoxy, fluoro, methyl, and trifluoromethyl and arenes in the presence of potassium tert-butoxide (4 equiv.) at 110 °C in 2-5 h. Substituted arenes such as toluene, xylene, anisole, and fluorobenzene also proceeded to form biaryls under AMVN-initiated reaction conditions. Moreover naphthalene, pyridine, pyrimidine, and pyridazine also coupled with aryl iodides and produced biaryls in 41-82% yields. It seems that AMVN initiates the formation of the aryl radical, which enters the radical chain reaction. The generated aryl radical may combine with the arene leading to a biaryl radical, which upon protonation gives the biphenyl radical anion and tert-butanol. The biphenyl radical anion finally reacts with the aryl iodide generating the aryl radical and thus completes the radical chain reaction with concomitant release of biphenyl.
- Bhakuni, Bhagat Singh,Yadav, Abhimanyu,Kumar, Shailesh,Kumar, Sangit
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p. 827 - 836
(2014/02/14)
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- Synthesis of pinacol arylboronates from aromatic amines: A metal-free transformation
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A metal-free borylation process based on Sandmeyer-type transformation using arylamines derivatives as the substrates has been developed. Through optimization of the reaction conditions, this novel conversion can be successfully applied to a wide range of aromatic amines, affording borylation products in moderate to good yields. Various functionalized arylboronates, which are difficult to access by other methods, can be easily obtained with this metal-free transformation. Moreover, this transformation can be followed by Suzuki-Miyaura cross-coupling without purification of the borylation products, which enhances the practical usefulness of this method. A possible reaction mechanism involving radical species has been proposed.
- Qiu, Di,Jin, Liang,Zheng, Zhitong,Meng, He,Mo, Fanyang,Wang, Xi,Zhang, Yan,Wang, Jianbo
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p. 1923 - 1933
(2013/03/29)
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- De novo synthesis of 1,4-dihydropyridines and pyridines
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An efficient and general method for the synthesis of 1,4-dihydropyridines and pyridines based on a lithiation/isomerization/intramolecular carbolithiation sequence is reported. This procedure provides an efficient, divergent, and straightforward entry to a wide range of polysubstituted dihydropyridines and pyridines starting from readily available N-allyl-ynamides.
- Gati, Wafa,Rammah, Mohamed M.,Rammah, Mohamed B.,Couty, Francois,Evano, Gwilherm
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supporting information; experimental part
p. 9078 - 9081
(2012/07/13)
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- Intramolecular carbolithiation of N-allyl-ynamides: An efficient entry to 1,4-dihydropyridines and pyridines - Application to a formal synthesis of sarizotan
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We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.
- Gati, Wafa,Rammah, Mohamed M.,Rammah, Mohamed B.,Evano, Gwilherm
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p. 2214 - 2222
(2013/02/23)
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- Ligand-promoted C3-selective arylation of pyridines with Pd catalysts: Gram-scale synthesis of (±)-preclamol
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The first example of Pd-catalyzed, C3-selective arylation of unprotected pyridines has been developed by employing a catalytic system consisting of Pd(OAc)2 and 1,10-phenanthroline. This protocol provides an expeditious route to an important class of 3-arylpyridines and 3-arylpiperidines frequently found in bioactive compounds. A brief synthesis of the drug molecule (±)-preclamol is also reported.
- Ye, Mengchun,Gao, Guo-Lin,Edmunds, Andrew J. F.,Worthington,Morris, James A.,Yu, Jin-Quan
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supporting information; experimental part
p. 19090 - 19093
(2012/01/07)
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- Phosphine-free cross-coupling reaction of halopyridines with arylboronic acids in an ionic liquid: Water mixture
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Palladium acetate-catalysed Suzuki reaction of halopyridines and arylboronic acids has been investigated in roomtemperature ionic liquids in the absence of the phosphine ligand. A significant effect of water on the efficiency of the Suzuki reaction in ionic liquids was observed. The mixture of ionic liquid and water significantly enhanced the rate of the coupling reaction. The separation of the product was easily performed by extraction with diethyl ether and the Pd(OAc)2-[bmim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) can be reused six times with only a small loss of reactivity.
- Xin, Bingwei
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experimental part
p. 412 - 415
(2009/06/30)
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