- C-O Bond Silylation Catalyzed by Iron: A General Method for the Construction of Csp2-Si Bonds
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The iron-catalyzed construction of Csp2-Si bonds via unreactive C-O bonds possesses a challenging topic in organic chemistry. Herein we report an iron-catalyzed silylation of aryl and alkenyl carbamates via C-O bond activation. This protocol fe
- Zhang, Juan,Zhang, Yun,Geng, Shasha,Chen, Shuo,Liu, Zhengli,Zeng, Xiaoqin,He, Yun,Feng, Zhang
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supporting information
p. 2669 - 2674
(2020/03/30)
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- Development and Mechanistic Studies of Iron-Catalyzed Construction of Csp2-B Bonds via C-O Bond Activation
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Herein we describe an iron-catalyzed borylation of alkenyl and aryl carbamates through the activation of a C-O bond. This protocol exhibits high efficiency, a broad substrate scope, and the late-stage borylation of biorelevant compounds, thus providing potential applications in medicinal chemistry. Moreover, this method enables orthogonal transformations of phenol derivatives and also offers good opportunities for the synthesis of multisubstituted arenes. Preliminary mechanistic studies suggest that a FeII/FeIII catalytic cycle via a radical pathway might be involved in the reaction.
- Geng, Shasha,Zhang, Juan,Chen, Shuo,Liu, Zhengli,Zeng, Xiaoqin,He, Yun,Feng, Zhang
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supporting information
p. 5582 - 5588
(2020/07/08)
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- N -Arylation of (hetero)arylamines using aryl sulfamates and carbamates via C-O bond activation enabled by a reusable and durable nickel(0) catalyst
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An effective and general aryl amination protocol has been developed using a magnetically recoverable Ni(0) based nanocatalyst. This new stable catalyst was prepared on Fe3O4@SiO2 modified by EDTA and investigated by FT-IR, EDX, TEM, XRD, DLS, FE-SEM, XPS, NMR, TGA, VSM, ICP and elemental analysis techniques. The reaction proceeded via carbon-oxygen bond cleavage of (hetero)aryl carbamates and sulfamates under simple and mild conditions without the use of any external ligands. This method demonstrated functional group tolerance in the N-arylation of various nitrogen-containing compounds as well as aliphatic amines, anilines, pyrroles, pyrazoles, imidazoles, indoles, and indazoles with good to excellent yields. Furthermore, the catalyst could be easily recovered by using an external magnetic field and directly reused at least six times without notable reduction in its activity. This journal is
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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p. 13266 - 13278
(2020/10/07)
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- Experimental and computational study of the 1,5-o → n carbamoyl snieckus-fries-type rearrangement
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The reactions of o-lithiated O-aryl N,N-diethylcarbamates with different C-N multiple bond electrophiles have been thoroughly studied. A 1,5-O → N carbamoyl shift, a new variation of the anionic Fries-type rearrangement, takes place when nitriles, imines, or alkylcarbodiimides are employed. In these cases, the carbamoyl group plays a dual role as a directing group, building up a variety of functional groups through the 1,5-O → N carbamoyl migration. On the other hand, the use of iso(thio)cyanates and arylcarbodiimides led to non-rearranged o-functionalized Oarylcarbamates. This reactivity was further computationally explored, and the governing factor could be traced back to the relative basicity of the alternative products (migrated vs nonmigrated substrates). This exploration also provided interesting insights about the degree of complexation of the lithium cations onto these substrates. A new access to useful 2-hydroxybenzophenone derivatives has also been developed.
- Feberero, Claudia,Lopez, Carlos Silva,Sanz, Roberto,Sedano, Carlos,Suarez-Pantiga, Samuel
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p. 12561 - 12578
(2020/11/09)
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- Directed ortho-Metalation of Aryl Amides, O-Carbamates, and Methoxymethoxy Systems: Directed Metalation Group Competition and Cooperation
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A systematic study on the competitive metalation of derivatives containing four directed metalation groups (DMGs), namely, Cl, OMe, methoxymethoxy (OMOM), and CONEt2, in comparison with the OCONEt2 DMG is described. In addition, the
- Miah, M. A. Jalil,Sibi, Mukund P.,Chattopadhyay,Familoni, Oluwole B.,Snieckus, Victor
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supporting information
p. 447 - 454
(2017/12/15)
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- 1,5-O → N Carbamoyl Snieckus-Fries-Type Rearrangement
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The reaction of o-lithiated O-aryl N,N-diethylcarbamates with (hetero)aromatic nitriles gives rise to functionalized salicylidene urea derivatives in high yields through a new 1,5-O → N carbamoyl migration. This Snieckus-Fries-type rearrangement nicely complements previously known O → C and O → O related shifts. In addition, when dimethylmalononitrile is used as the electrophilic partner, the carbamoyl shift is preferred over the expected transnitrilation reaction.
- Feberero, Claudia,Suárez-Pantiga, Samuel,Cabello, Zaida,Sanz, Roberto
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supporting information
p. 2437 - 2440
(2018/04/27)
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- A copper-catalyzed oxidative coupling reaction of arylboronic acids, amines and carbon dioxide using molecular oxygen as the oxidant
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A Cu-catalyzed oxidative coupling reaction of arylboronic acids, amines and carbon dioxide is described for the first time in this paper. The reaction tolerates a wide range of functional groups, providing a convenient protocol for the synthesis of various O-aryl carbamates. The successful development of the transformation was enabled by the use of BF3·OEt2 as the promoter and molecular oxygen as the oxidant. Mechanistic studies suggested that the CuII carbamato complex is involved in the catalytic transformation.
- Xiong, Wenfang,Qi, Chaorong,Guo, Tianzuo,Zhang, Min,Chen, Kai,Jiang, Huanfeng
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supporting information
p. 1642 - 1645
(2017/06/05)
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- Lithiation of a silyl ether: Formation of an ortho-fries hydroxyketone
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A hydroxy-directed alkylation of an N,N-diethylarylamide using CIPE-assisted α-silyl carbanions (CIPE=complex-induced proximity effect) has been developed using a simple reagent combination of LDA (lithium diisopropylamide) and chlorosilane. A study of the mechanism, and the application of the procedure to an anionic Snieckus-Fries rearrangement for a highly efficient synthesis of the potent phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, are reported.
- Lo, Hong-Jay,Lin, Chin-Yin,Tseng, Mei-Chun,Chein, Rong-Jie
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supporting information
p. 9026 - 9029
(2014/09/17)
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- Nickel catalyzed cross-coupling of aryl C-O based electrophiles with aryl neopentylglycolboronates
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The efficiency of mesylates, sulfamates, esters, carbonates, carbamates, and methyl ethers as C-O-based electrophiles attached to the 1- or 2-position of naphthalene and to activated and nonactivated phenyl substrates was compared for the first time in Ni-catalyzed cross-coupling with phenyl neopentylglycolboronates containing electron-rich and electron-deficient substituents in their para-position. These experiments were performed in the presence of four different Ni(II)- and Ni(0)-based catalysts. Ni(II)-based catalysts mediate the cross-coupling of most 2-naphthyl C-O electrophiles with both arylboronic acids and with neopentylglycolboronates when K 3PO4 is used as base. The same catalysts are not efficient when CsF is used as base. However, Ni(0)-based catalysts exhibit selective efficiency, and when reactive, their efficiency is higher than that of Ni(II)-based catalysts in the presence of both K3PO4 and CsF. These results provide both reaction conditions for the cross-coupling, and for the elaboration of orthogonal cross-coupling methodologies of various C-O based electrophiles with aryl neopentylglycolboronates. With the exception of mesylates and sulfamates the efficiency of all other 2-naphthyl C-O electrophiles was lower in cross-coupling with aryl neopentylglycolboronates than with arylboronic acids
- Leowanawat, Pawaret,Zhang, Na,Percec, Virgil
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experimental part
p. 1018 - 1025
(2012/03/22)
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- Suzuki-Miyaura coupling of aryl carbamates, carbonates, and sulfamates
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(Chemical Equation Presented) The first Suzuki-Miyaura cross-couplings of carbamates, carbonates, and sulfamates is described. The method provides a powerful means of using simple derivatives of phenol as precursors to polysubstituted aromatic compounds, as exemplified by a concise synthesis of the anti-inflammatory drug flurbiprofen.
- Quasdorf, Kyle W.,Riener, Michelle,Petrova, Krastina V.,Garg, Neil K.
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supporting information; experimental part
p. 17748 - 17749
(2010/04/01)
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- Atropisomeric benzamides and naphthamides as chiral auxiliaries
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Atropisomeric compounds whose chirality resides in a rotationally restricted aryl-CONR2 bond may be employed as chiral auxiliaries. The electron-withdrawing amide group causes problems in the diastereoselective functionalisation of enolates derived from atropisomeric phenyl esters, but a strategy based on atroposelective nucleophilic addition to a chiral aldehyde followed by stereospecific [3,3] sigmatropic rearrangement allows atropisomeric naphthamides to be used as auxiliaries. The auxiliaries are resolved by dynamic resolution during aminal formation using a proline-derived diamine. The Royal Society of Chemistry 2000.
- Clayden, Jonathan,Helliwell, Madeleine,McCarthy, Catherine,Westlund, Neil
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p. 3232 - 3249
(2007/10/03)
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