The Experts below are selected from a list of 5703 Experts worldwide ranked by ideXlab platform
Daniel J Weix - One of the best experts on this subject based on the ideXlab platform.
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nickel catalyzed cross Electrophile coupling of aryl chlorides with primary alkyl chlorides
2020Co-Authors: S Kim, Matthew J Goldfogel, Michael M Gilbert, Daniel J WeixAbstract:Alkyl chlorides and aryl chlorides are among the most abundant and stable carbon Electrophiles. Although their coupling with carbon nucleophiles is well developed, the cross-Electrophile coupling of aryl chlorides with alkyl chlorides has remained a challenge. We report here the first general approach to this transformation. The key to productive, selective cross-coupling is the use of a small amount of iodide or bromide along with a recently reported ligand, pyridine-2,6-bis(N-cyanocarboxamidine) (PyBCamCN). The scope of the reaction is demonstrated with 35 examples (63 ± 16% average yield), and we show that the Br- and I- additives act as cocatalysts, generating a low, steady-state concentration of more-reactive alkyl bromide/iodide.
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methods and mechanisms for cross Electrophile coupling of csp2 halides with alkyl Electrophiles
2015Co-Authors: Daniel J WeixAbstract:ConspectusCross-Electrophile coupling, the cross-coupling of two different Electrophiles, avoids the need for preformed carbon nucleophiles, but development of general methods has lagged behind cross-coupling and C–H functionalization. A central reason for this slow development is the challenge of selectively coupling two substrates that are alike in reactivity. This Account describes the discovery of generally cross-selective reactions of aryl halides and acyl halides with alkyl halides, the mechanistic studies that illuminated the underlying principles of these reactions, and the use of these fundamental principles in the rational design of new cross-Electrophile coupling reactions.Although the coupling of two different Electrophiles under reducing conditions often leads primarily to symmetric dimers, the subtle differences in reactivity of aryl halides and alkyl halides with nickel catalysts allowed for generally cross-selective coupling reactions. These conditions could also be extended to the couplin...
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cross Electrophile coupling principles of reactivity and selectivity
2014Co-Authors: Daniel A. - ) Everson, Daniel J WeixAbstract:A critical overview of the catalytic joining of two different Electrophiles, cross-Electrophile coupling (XEC), is presented with an emphasis on the central challenge of cross-selectivity. Recent synthetic advances and mechanistic studies have shed light on four possible methods for overcoming this challenge: (1) employing an excess of one reagent; (2) electronic differentiation of starting materials; (3) catalyst–substrate steric matching; and (4) radical chain processes. Each method is described using examples from the recent literature.
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mechanism and selectivity in nickel catalyzed cross Electrophile coupling of aryl halides with alkyl halides
2013Co-Authors: Soumik Biswas, Daniel J WeixAbstract:The direct cross-coupling of two different Electrophiles, such as an aryl halide with an alkyl halide, offers many advantages over conventional cross-coupling methods that require a carbon nucleophile. Despite its promise as a versatile synthetic strategy, a limited understanding of the mechanism and origin of cross selectivity has hindered progress in reaction development and design. Herein, we shed light on the mechanism for the nickel-catalyzed cross-Electrophile coupling of aryl halides with alkyl halides and demonstrate that the selectivity arises from an unusual catalytic cycle that combines both polar and radical steps to form the new C–C bond.
Xingzhong Shu - One of the best experts on this subject based on the ideXlab platform.
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dynamic kinetic cross Electrophile arylation of benzyl alcohols by nickel catalysis
2021Co-Authors: Peng Guo, Ke Wang, Wenjie Jin, Hao Xie, Xueyuan Liu, Xingzhong ShuAbstract:Catalytic transformation of alcohols via metal-catalyzed cross-coupling reactions is very important, but it typically relies on a multistep procedure. We here report a dynamic kinetic cross-coupling approach for the direct functionalization of alcohols. The feasibility of this strategy is demonstrated by a nickel-catalyzed cross-Electrophile arylation reaction of benzyl alcohols with (hetero)aryl Electrophiles. The reaction proceeds with a broad substrate scope of both coupling partners. The electron-rich, electron-poor, and ortho-/meta-/para-substituted (hetero)aryl Electrophiles (e.g., Ar-OTf, Ar-I, Ar-Br, and inert Ar-Cl) all coupled well. Most of the functionalities, including aldehyde, ketone, amide, ester, nitrile, sulfone, furan, thiophene, benzothiophene, pyridine, quinolone, Ar-SiMe3, Ar-Bpin, and Ar-SnBu3, were tolerated. The dynamic nature of this method enables the direct arylation of benzylic alcohol in the presence of various nucleophilic groups, including nonactivated primary/secondary/tertiary alcohols, phenols, and free indoles. It thus offers a robust alternative to existing methods for the precise construction of diarylmethanes. The synthetic utility of the method was demonstrated by a concise synthesis of biologically active molecules and by its application to peptide modification and conjugation. Preliminary mechanistic studies revealed that the reaction of in situ formed benzyl oxalates with nickel, possibly via a radical process, is an initial step in the reaction with aryl Electrophiles.
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cross Electrophile c sp2 si coupling of vinyl chlorosilanes
2020Co-Authors: Jicheng Duan, Ke Wang, Xueyuan Liu, Shaolin Kang, Xingzhong ShuAbstract:The cross-Electrophile coupling has become a powerful tool for C-C bond formation, but its potential for forging the C-Si bond remains unexplored. Here we report a cross-Electrophile Csp2 -Si coupling reaction of vinyl/aryl Electrophiles with vinyl chlorosilanes. This new protocol offers an approach for facile and precise synthesis of organosilanes with high molecular diversity and complexity from readily available materials. The reaction proceeds under mild and non-basic conditions, demonstrating a high step economy, broad substrate scope, wide functionality tolerance, and easy scalability. The synthetic utility of the method is shown by its efficient accessing of silicon bioisosteres, the design of new BCB-monomers, and studies on the Hiyama cross-coupling of vinylsilane products.
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highly enantioselective cross Electrophile aryl alkenylation of unactivated alkenes
2019Co-Authors: Zhi-xiong Tian, Xueyuan Liu, Jicheng Duan, Jin-bao Qiao, Xiaobo Pang, Zhen-zhen Zhao, Xingzhong ShuAbstract:Enantioselective cross-Electrophile reactions remain a challenging subject in metal catalysis, and with respect to data, studies have mainly focused on stereoconvergent reactions of racemic alkyl Electrophiles. Here, we report an enantioselective cross-Electrophile aryl-alkenylation reaction of unactivated alkenes. This method provides access to a number of biologically important chiral molecules such as dihydrobenzofurans, indolines, and indanes. The incorporated alkenyl group is suitable for further reactions that can lead to an increase in molecular diversity and complexity. The reaction proceeds under mild conditions at room temperature, and an easily accessible chiral pyrox ligand is used to afford products with high enantioselectivity. The synthetic utility of this method is demonstrated by enabling the modification of complex molecules such as peptides, indometacin, and steroids.
Hegui Gong - One of the best experts on this subject based on the ideXlab platform.
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ni catalyzed cross Electrophile coupling of aryl triflates with thiocarbonates via c o c o bond cleavage
2021Co-Authors: Zhaodong Zhu, Yuxin Gong, Weiqi Tong, Weichao Xue, Hegui GongAbstract:A nickel-catalyzed reductive coupling of aryl triflates with thiocarbonates is reported here. Both electron-rich and -deficient aryl C(sp2)-O Electrophiles as well as a class of O-tBu S-alkyl thiocarbonates are compatible with the optimized reaction conditions, as evidenced by 49 examples. The reaction also proceeds with good chemoselective cleavage of the C-O bond with regard to thioesters. This work broadens the scope of nickel-catalyzed reductive cross-Electrophile coupling reactions.
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nickel catalyzed methylation of aryl halides tosylates with methyl tosylate
2017Co-Authors: Jiawang Wang, Jianhong Zhao, Hegui GongAbstract:This work describes the cross-Electrophile methylation of aryl bromides and aryl tosylates with methyl tosylate. The mild reaction conditions allow effective methylation of a wide set of heteroaryl Electrophiles and dimethylation of dibromoarenes.
Xueyuan Liu - One of the best experts on this subject based on the ideXlab platform.
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dynamic kinetic cross Electrophile arylation of benzyl alcohols by nickel catalysis
2021Co-Authors: Peng Guo, Ke Wang, Wenjie Jin, Hao Xie, Xueyuan Liu, Xingzhong ShuAbstract:Catalytic transformation of alcohols via metal-catalyzed cross-coupling reactions is very important, but it typically relies on a multistep procedure. We here report a dynamic kinetic cross-coupling approach for the direct functionalization of alcohols. The feasibility of this strategy is demonstrated by a nickel-catalyzed cross-Electrophile arylation reaction of benzyl alcohols with (hetero)aryl Electrophiles. The reaction proceeds with a broad substrate scope of both coupling partners. The electron-rich, electron-poor, and ortho-/meta-/para-substituted (hetero)aryl Electrophiles (e.g., Ar-OTf, Ar-I, Ar-Br, and inert Ar-Cl) all coupled well. Most of the functionalities, including aldehyde, ketone, amide, ester, nitrile, sulfone, furan, thiophene, benzothiophene, pyridine, quinolone, Ar-SiMe3, Ar-Bpin, and Ar-SnBu3, were tolerated. The dynamic nature of this method enables the direct arylation of benzylic alcohol in the presence of various nucleophilic groups, including nonactivated primary/secondary/tertiary alcohols, phenols, and free indoles. It thus offers a robust alternative to existing methods for the precise construction of diarylmethanes. The synthetic utility of the method was demonstrated by a concise synthesis of biologically active molecules and by its application to peptide modification and conjugation. Preliminary mechanistic studies revealed that the reaction of in situ formed benzyl oxalates with nickel, possibly via a radical process, is an initial step in the reaction with aryl Electrophiles.
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cross Electrophile c sp2 si coupling of vinyl chlorosilanes
2020Co-Authors: Jicheng Duan, Ke Wang, Xueyuan Liu, Shaolin Kang, Xingzhong ShuAbstract:The cross-Electrophile coupling has become a powerful tool for C-C bond formation, but its potential for forging the C-Si bond remains unexplored. Here we report a cross-Electrophile Csp2 -Si coupling reaction of vinyl/aryl Electrophiles with vinyl chlorosilanes. This new protocol offers an approach for facile and precise synthesis of organosilanes with high molecular diversity and complexity from readily available materials. The reaction proceeds under mild and non-basic conditions, demonstrating a high step economy, broad substrate scope, wide functionality tolerance, and easy scalability. The synthetic utility of the method is shown by its efficient accessing of silicon bioisosteres, the design of new BCB-monomers, and studies on the Hiyama cross-coupling of vinylsilane products.
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highly enantioselective cross Electrophile aryl alkenylation of unactivated alkenes
2019Co-Authors: Zhi-xiong Tian, Xueyuan Liu, Jicheng Duan, Jin-bao Qiao, Xiaobo Pang, Zhen-zhen Zhao, Xingzhong ShuAbstract:Enantioselective cross-Electrophile reactions remain a challenging subject in metal catalysis, and with respect to data, studies have mainly focused on stereoconvergent reactions of racemic alkyl Electrophiles. Here, we report an enantioselective cross-Electrophile aryl-alkenylation reaction of unactivated alkenes. This method provides access to a number of biologically important chiral molecules such as dihydrobenzofurans, indolines, and indanes. The incorporated alkenyl group is suitable for further reactions that can lead to an increase in molecular diversity and complexity. The reaction proceeds under mild conditions at room temperature, and an easily accessible chiral pyrox ligand is used to afford products with high enantioselectivity. The synthetic utility of this method is demonstrated by enabling the modification of complex molecules such as peptides, indometacin, and steroids.
Jicheng Duan - One of the best experts on this subject based on the ideXlab platform.
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cross Electrophile c sp2 si coupling of vinyl chlorosilanes
2020Co-Authors: Jicheng Duan, Ke Wang, Xueyuan Liu, Shaolin Kang, Xingzhong ShuAbstract:The cross-Electrophile coupling has become a powerful tool for C-C bond formation, but its potential for forging the C-Si bond remains unexplored. Here we report a cross-Electrophile Csp2 -Si coupling reaction of vinyl/aryl Electrophiles with vinyl chlorosilanes. This new protocol offers an approach for facile and precise synthesis of organosilanes with high molecular diversity and complexity from readily available materials. The reaction proceeds under mild and non-basic conditions, demonstrating a high step economy, broad substrate scope, wide functionality tolerance, and easy scalability. The synthetic utility of the method is shown by its efficient accessing of silicon bioisosteres, the design of new BCB-monomers, and studies on the Hiyama cross-coupling of vinylsilane products.
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highly enantioselective cross Electrophile aryl alkenylation of unactivated alkenes
2019Co-Authors: Zhi-xiong Tian, Xueyuan Liu, Jicheng Duan, Jin-bao Qiao, Xiaobo Pang, Zhen-zhen Zhao, Xingzhong ShuAbstract:Enantioselective cross-Electrophile reactions remain a challenging subject in metal catalysis, and with respect to data, studies have mainly focused on stereoconvergent reactions of racemic alkyl Electrophiles. Here, we report an enantioselective cross-Electrophile aryl-alkenylation reaction of unactivated alkenes. This method provides access to a number of biologically important chiral molecules such as dihydrobenzofurans, indolines, and indanes. The incorporated alkenyl group is suitable for further reactions that can lead to an increase in molecular diversity and complexity. The reaction proceeds under mild conditions at room temperature, and an easily accessible chiral pyrox ligand is used to afford products with high enantioselectivity. The synthetic utility of this method is demonstrated by enabling the modification of complex molecules such as peptides, indometacin, and steroids.
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Highly Enantioselective Cross-Electrophile Aryl-Alkenylation of Unactivated Alkenes
2019Co-Authors: Zhi-xiong Tian, Jin-bao Qiao, Xiaobo Pang, Zhen-zhen Zhao, Jicheng DuanAbstract:Enantioselective cross-Electrophile reactions remain a challenging subject in metal catalysis, and with respect to data, studies have mainly focused on stereoconvergent reactions of racemic alkyl Electrophiles. Here, we report an enantioselective cross-Electrophile aryl-alkenylation reaction of unactivated alkenes. This method provides access to a number of biologically important chiral molecules such as dihydrobenzofurans, indolines, and indanes. The incorporated alkenyl group is suitable for further reactions that can lead to an increase in molecular diversity and complexity. The reaction proceeds under mild conditions at room temperature, and an easily accessible chiral pyrox ligand is used to afford products with high enantioselectivity. The synthetic utility of this method is demonstrated by enabling the modification of complex molecules such as peptides, indometacin, and steroids
