- Copper-Catalyzed Ullmann-Type Coupling and Decarboxylation Cascade of Arylhalides with Malonates to Access α-Aryl Esters
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We have developed a high-efficiency and practical Cu-catalyzed cross-coupling to directly construct versatile α-aryl-esters by utilizing readily available aryl bromides (or chlorides) and malonates. These gram-scale approaches occur with turnovers of up to 1560 and are smoothly conducted by the usage of a low catalyst loading, a new available ligand, and a green solvent. A variety of functional groups are tolerated, and the application occurs with α-aryl-esters to access nonsteroidal anti-inflammatory drugs (NSAIDs) on the gram scale.
- Cheng, Fei,Chen, Tao,Huang, Yin-Qiu,Li, Jia-Wei,Zhou, Chen,Xiao, Xiao,Chen, Fen-Er
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supporting information
p. 115 - 120
(2022/01/04)
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- Gold Complexes with ADAP Ligands: Effect of Bulkiness in Catalytic Carbene Transfer Reactions (ADAP = Alkoxydiaminophosphine)
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A family of gold(I) complexes of composition AuCl(ADAP) (ADAP = alkoxydiaminophosphine) has been synthetized through a one-pot simple protocol in which the ADAP ligand is prepared in situ before reaction with the Au(I) source. Structural data demonstrate that these ADAP ligands exert a trans effect superior to those of phosphine or phosphite ligands. Evaluation of the buried volume (percentVBur) indicates a steric hindrance higher than those of several NHC, PR3, and P(OR3) ligands, in the context of AuCl(L) complexes. These complexes promote the catalytic transfer of a carbene group from ethyl diazoacetate to alkenes and alkanes. In the case of styrene, both the Csp2-H bonds and the Ca? C bond are functionalized, the relative ratio depending on the catalyst employed and correlating well with the percentVBur value. Data available allow proposing that these compounds display quite similar electronic properties but differ in steric properties, a variable that can be readily controlled upon modifying the alkoxy group at the ADAP ligand by simply replacing the starting alcohol employed in the synthesis.
- Fructos, Manuel R.,Molina, Francisco,Pérez, Pedro J.,Pizarro, Juan Diego
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supporting information
(2020/07/14)
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- Mechanistic studies on gold-catalyzed direct arene c-h bond functionalization by carbene insertion: The coinage-metal effect
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The catalytic functionalization of the Csp2-H bond of benzene by means of the insertion of the CHCO2Et group from ethyl diazoacetate (N2= CHCO2Et) has been studied with the series of coinage-metal complexes IPrMCl (IPr = 1,3-bis- (diisopropylphenyl)imidazol-2-ylidene) and NaBArF 4 (BArF 4 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate). For Cu and Ag, these examples constitute the first use of such metals toward this transformation, which also provides ethyl cyclohepta-2,4,6-trienecarboxylate as a byproduct from the so-called Buchner reaction. In the case of methyl-substituted benzenes, the reaction exclusively proceeds onto the aromatic ring, the Csp3-H bond remaining unreacted. A significant coinage-metal effect has been observed, since the gold catalyst favors the formation of the insertion product into the Csp2-H bond whereas copper and silver preferentially induce the formation of the cycloheptatriene derivative. Experimental studies and theoretical calculations have explained the observed selectivity in terms of the formation of a common Wheland intermediate, resembling an electrophilic aromatic substitution, from which the reaction pathway evolves into two separate routes to each product.
- Fructos, Manuel R.,Besora, Maria,Braga, Ataualpa A. C,Díaz-Requejo, M. Mar,Maseras, Feliu,Perez, Pedro J.
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supporting information
p. 172 - 179
(2017/04/04)
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- Synthesis of α-aryl esters and nitriles: Deaminative coupling of α-aminoesters and α-aminoacetonitriles with arylboronic acids
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Transition-metal-free synthesis of α-aryl esters and nitriles using arylboronic acids with α-aminoesters and α-aminoacetonitriles, respectively, as the starting materials has been developed. The reaction represents a rare case of converting C(sp3)-N bonds into C(sp3)-C(sp2) bonds. The reaction conditions are mild, demonstrate good functional-group tolerance, and can be scaled up. Touch base: A transition-metal-free protocol for the synthesis of α-aryl esters and nitriles by deaminative coupling is presented. Strong bases and transition-metal catalysts are not needed. The new synthetic method uses readily available starting materials and demonstrates wide substrate scope.
- Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Zhang, Yan,Wang, Jianbo
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supporting information
p. 10510 - 10514
(2016/02/18)
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- Synthesis of α-Aryl nitriles through palladium-catalyzed decarboxylative coupling of cyanoacetate salts with aryl halides and triflates
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Worth its salt: The palladium-catalyzed decarboxylative coupling of the cyanoacetate salt as well as its mono- and disubstituted derivatives with aryl chlorides, bromides, and triflates is described (see scheme). This reaction is potentially useful for the preparation of a diverse array of α-aryl nitriles and has good functional group tolerance. S-Phos=2-(2,6- dimethoxybiphenyl)dicyclohexylphosphine), Xant-Phos=4,5-bis(diphenylphosphino)- 9,9-dimethylxanthene. Copyright
- Shang, Rui,Ji, Dong-Sheng,Chu, Ling,Fu, Yao,Liu, Lei
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supporting information; experimental part
p. 4470 - 4474
(2011/06/24)
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- A gold catalyst for carbene-transfer reactions from ethyl diazoacetate
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(Chemical Equation Presented) Approaching El Dorado: A gold catalyst has been discovered that transfers a carbene unit from ethyl diazoacetate to aromatic substrates (see scheme) as well as olefins, amines, and alcohols. The insertion of carbene units into the C-H bonds of the aromatic ring of benzene, toluene, and styrene is a novel reaction. R = H, CH3, CH=CH 2; IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene.
- Fructos, Manuel R.,Belderrain, Tomas R.,De Fremont, Pierre,Scott, Natalie M.,Nolan, Steven P.,Diaz-Requejo, M Mar,Perez, Pedro J.
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p. 5284 - 5288
(2007/10/03)
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