Article
Chemistry, Organic
Zhu Cao, Huihui Zhang, Xinxin Wu, Yahong Li, Chen Zhu
Summary: The research achieved the heteroarylation of unactivated aliphatic C-H bonds through radical-mediated heteroaryl migration, leading to a variety of heteroaryl-substituted aliphatic ketones. The method is applicable to O-/S-/N-containing heteroaryls and features mild C-C bond cleavage and good selectivity for tertiary C-H bonds.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Inorganic & Nuclear
Bijoy Ghosh, Felipe Fantuzzi, Ashwini K. Phukan
Summary: Density functional theory calculations were conducted on metallatranes containing group 13 elements at the bridgehead position to study the M center dot center dot center dot Z interaction and reactivity at the metal center. The strength of the M center dot center dot center dot Z interaction was found to increase with the size and polarizability of the bridgehead group 13 elements. The binding of Lewis bases to the metallatranes was significantly more exergonic for the larger In(III) ions.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Jiayuan Wang, Youwan Ye, Tongzhi Sang, Chenxing Zhou, Xiazhen Bao, Yong Yuan, Congde Huo
Summary: A general C(sp3)-H/C(sp3)-H dehydrogenative coupling strategy for the preparation of various natural or unnatural amino acids from readily available glycine derivatives and hydrocarbons is reported, which involves a combination of SET and HAT process.
Article
Chemistry, Physical
Akira Matsumoto, Masanori Yamamoto, Keiji Maruoka
Summary: A series of HAT catalysts based on the DABCO structure were designed for photoinduced HAT catalysis, enabling efficient and site-selective C-H alkylation. The addition of substituents adjacent to a nitrogen atom on the catalyst further improved the site selectivity according to mechanistic studies.
Article
Chemistry, Multidisciplinary
Ricardo I. Rodriguez, Leonardo Mollari, Jose Aleman
Summary: This study introduces a light-driven, atom-economical process for synthesizing enantiomerically enriched substituted chiral 1-pyrroline derivatives through distal functionalization of acyl heterocycles and the use of tailor-made ketimines as partners. Water is the sole by-product of the reaction, and stereoselectivity is controlled by coordination to a chiral-at-rhodium catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Subrata K. Ghosh, Mengnan Hu, Robert J. Comito
Summary: The method describes a mild and selective protocol for preparing primary and secondary aliphatic amines in a single pot based on intermolecular sp(3) C-H imination. It constitutes a selective method for complex amine synthesis and a new mechanistic platform for C-H amination. This work demonstrates useful site selectivity within substrates bearing multiple sp(3) C-H bonds.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Applied
Han Gao, Lin Guo, Chengcheng Shi, Yining Zhu, Chao Yang, Wujiong Xia
Summary: A transition-metal-free photoinduced radical-mediated alpha-oxy C-H cyclobutylation reaction was developed, which enables the synthesis of 1,3-disubstituted cyclobutanes in high yields. The reaction proceeds via photo-induced hydrogen atom transfer to generate alpha-oxy carbon-centered radical intermediates.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Polymer Science
Xiaoling Xu, Mei Hong, Chunyang Bao, Yan Wang, Jing Chen, Die Li, Tianheng Wang, Qiang Zhang
Summary: The claw-type Schiff base Py(3)Tren was utilized as an active ligand for photoinduced atom transfer radical polymerization (Photo-ATRP) with CuBr2 as the catalyst, enabling temporal control of the polymerization process and synthesis of well-defined poly(MMA) with high chain-end functionality confirmed by in situ chain extension. The polymerization mechanism was elucidated through UV/vis spectroscopy and electrospray ionization mass spectrometry (ESI-MS) experiments.
Review
Chemistry, Multidisciplinary
Ruoyu Li, Weina Kong, Zesheng An
Summary: This Minireview discusses the key roles enzymes play in reversible deactivation radical polymerization (Enz-RDRP) and highlights their applications in surface brush fabrication, sensing, polymerization-induced self-assembly, and high-throughput synthesis. The authors also reflect on the challenges and future directions of this emerging area.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Laurent Vanoye, Boris Guicheret, Camila Rivera-Carcamo, Jeremy Audevard, Javier Navarro-Ruiz, Iker del Rosal, Iann C. Gerber, Cristian H. Campos, Bruno Fernandes Machado, Jerome Volkman, Regis Philippe, Philippe Serp, Alain Favre-Reguillon
Summary: This study reports on the synthesis, characterization, and kinetic evaluation of two highly active Pd catalysts supported on different carbon supports. The activities of both catalysts were high due to the unique cooperative catalysis between Pd single atoms and nanoparticles. However, heat management during the reactor operation with these catalysts is crucial to avoid deactivation and thermal runaway.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Jonas Elfert, Anup Bhunia, Constantin G. Daniliuc, Armido Studer
Summary: In this study, a radical transformation that enables intramolecular oxygen atom transfer to alkenes using the nitro functionality in nitroarenes as an oxygen donor is disclosed. The reaction proceeds via iron-catalyzed metal hydrogen atom transfer to alkenes and subsequent oxygenation, resulting in alkene hydration. Compared to intermolecular radical oxygenation, the intramolecular variant offers advantages, particularly in terms of diastereoselective radical hydration of conformationally flexible alkenes. The aryl moiety connecting the reactive NO2-functionality to the alkene substrate can be cleaved after oxygen transfer, yielding products derived from a formal diastereoselective intermolecular alkene hydration. Additionally, the resulting aniline entity after oxygen transfer can be used for the construction of nitrogen-containing heterocycles.
Article
Chemistry, Physical
Cheol Hyeon Ka, Da Seul Lee, Eun Jin Cho
Summary: This work investigates the solvent-dependent photochemistry of 2-tert-butyl-1,4-benzoquinones and achieves three selective transformations under different solvent conditions.
Article
Chemistry, Multidisciplinary
Benjamin S. Mitchell, Andrei Chirila, Jonathan A. Kephart, Andrew C. Boggiano, Sebastian M. Krajewski, Dylan Rogers, Werner Kaminsky, Alexandra Velian
Summary: This study provides atomistic insights into the interface between a single-site catalyst and a transition metal chalcogenide support and highlights the importance of redox cooperativity between the catalyst and support for achieving peak catalytic activity. By systematically probing the electronic and structural changes that occur as the identity of the metal varies, the researchers designed a molecular platform to investigate the interactions between the active site and the support. The study found that all 3d transition metal clusters displayed remarkable catalytic activity, with Mn and Co derivatives showing the fastest turnover. The researchers also characterized the clusters using various techniques, such as X-ray diffraction and nuclear magnetic resonance spectroscopy, to understand the structural, electronic, and magnetic properties. The study reveals that the reactivity of key metal-nitrenoid intermediates can be increased by maximizing the redox cooperativity between the edge metal and the support.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Zhan-Lin Wang, Fei Wang
Summary: Radical-mediated sp(3) C-H functionalization has wide applications in synthesis and derivatization. The site-selectivity of a reaction is determined by bond strength, polarity, steric accessibility, and acceptor properties. Activating primary C-H bonds selectively has been a difficult task, but recent attempts focus on exploring the steric effects of acceptors.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
G. Nottoli, B. Ballotta, S. Rampino
Summary: Charge-displacement (CD) analysis is a quantitative method for analyzing charge redistribution during intermolecular interactions. However, when complex interactions involving multiple concurrent charge flows occur, ordinary CD analysis only provides an averaged picture. In this study, LCD analysis, which combines CD analysis with Hirshfeld partitioning, allows for a detailed characterization of individual charge flows.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Marco Cianfanelli, Giorgio Olivo, Michela Milan, Robertus J. M. Klein Gebbink, Xavi Ribas, Massimo Bietti, Miquel Costas
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Physical
Margarida Borrell, Sergio Gil-Caballero, Massimo Bietti, Miquel Costas
Article
Chemistry, Multidisciplinary
Laia Vicens, Massimo Bietti, Miquel Costas
Summary: The use of bioinspired manganese catalysts and H2O2 under mild conditions allows for the efficient preparation of modified alpha-amino acids. This method demonstrates outstanding site-selectivity and diastereoselectivity, potentially serving as an alternative to established organometallic procedures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Teo Martin, Marco Galeotti, Michela Salamone, Fengjiao Liu, Yanmin Yu, Meng Duan, K. N. Houk, Massimo Bietti
Summary: A study on the reactions of the cumyloxyl radical with monosubstituted cyclopentanes and cyclohexanes showed that cyclopentanes predominantly functionalize at C-1, while the importance of HAT from C-1 decreases with increasing steric bulk in cyclohexanes. Determinants of site-selectivity include the nature of the HAT reagent, C-H bond strengths, and torsional effects.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Michela Salamone, Marco Galeotti, Eduardo Romero-Montalvo, Jeffrey A. van Santen, Benjamin D. Groff, James M. Mayer, Gino A. DiLabio, Massimo Bietti
Summary: The study investigated the applicability of the Evans-Polanyi relationship in HAT reactions, measured rate constants for HAT from C-H bonds to the cumyloxyl radical, and calculated consistent gas-phase C-H bond dissociation enthalpies. The analysis revealed distinct behaviors for different groups of substrates, indicating a qualitative connection between Bernasconi's principle of nonperfect synchronization and Marcus theory.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Marco Galeotti, Chiara Trasatti, Sergio Sisti, Michela Salamone, Massimo Bietti
Summary: A kinetic study was conducted to investigate the hydrogen atom transfer (HAT) reactions from nitrogen-containing heterocycles to the cumyloxyl radical. The study revealed that HAT occurs through hyperconjugative overlap between the C-H bonds and the N-C???O π system. The size of the ring and the functional group have significant effects on the reaction rate.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Fengjiao Liu, Siqi Ma, Zeying Lu, Anjanay Nangia, Meng Duan, Yanmin Yu, Guochao Xu, Ye Mei, Massimo Bietti, K. N. Houk
Summary: Density functional theory calculations were employed to study the reactions of radicals with C-H bonds in different environments, and modified Evans-Polanyi treatments were used to analyze the variations in activation barriers, with a focus on polarity and unsaturation effects. The study revealed the quantitative importance of the thermodynamics of reactions and polar effects in determining barriers to reactions involving radicals and C-H bonds.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Marco Galeotti, Laia Vicens, Michela Salamone, Miquel Costas, Massimo Bietti
Summary: The C(sp(3))-H bond oxygenation of cyclopropane-containing mechanistic probes has been studied using hydrogen peroxide catalyzed by manganese complexes. The study showed the presence of both unrearranged and rearranged oxygenation products, suggesting the involvement of cationic intermediates and different pathways. The selective formation of either unrearranged or rearranged product in high yield can be achieved by choosing appropriate catalyst structure and reaction conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Sergio Sisti, Fabio Ioele, Filippo Scarchilli, Marco Galeotti, Gino A. Dilabio, Michela Salamone, Massimo Bietti
Summary: Kinetic and product studies were conducted on the reactions of tert-alkoxyl radicals with secondary and tertiary alkanamides bearing benzylic alpha-C H bonds. The results revealed the exclusive HAT from the benzylic alpha-C H bonds, indicating a lack of benzylic activation and the presence of steric and stereoelectronic effects. In the isoindoline and tetrahydroisoquinoline derivatives, significant increases in kH were observed due to optimal overlap with both the phenyl p-system and the amide p-system or amine nitrogen lone pair, demonstrating the strong contribution of stereoelectronic activation.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Marco Galeotti, Woojin Lee, Sergio Sisti, Martina Casciotti, Michela Salamone, K. N. Houk, Massimo Bietti
Summary: A product and DFT computational study was conducted on the reactions of 3-ethyl-3-(trifluoromethyl)dioxirane (ETFDO) with bicyclic and spirocyclic hydrocarbons bearing cyclopropyl groups. The reactions exhibited good site-selectivities and diastereoselectivities, which were supported by calculated activation free energies. The computational results showed that hyperconjugative interactions between the cyclopropane C-C bonding orbitals and the sigma* orbitals of the C-H bonds activated these bonds towards hydrogen atom transfer to ETFDO.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Sergio Sisti, Marco Galeotti, Filippo Scarchilli, Michela Salamone, Miquel Costas, Massimo Bietti
Summary: A detailed study on C(sp(3))-H bond oxygenation reactions catalyzed by [Mn(OTf)(2)((TIPS)mcp)] complex was conducted, showing that the introduction of electron-withdrawing functional groups in different solvents significantly increased site-selectivity and product yield. The study also achieved selective control over multiple methylenic sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Andrea Palone, Guillem Casadevall, Sergi Ruiz-Barragan, Arnau Call, Siilvia Osuna, Massimo Bietti, Miquel Costas
Summary: This study describes a catalytic enantioselective hydroxylation method of tertiary C-H bonds in cyclohexane scaffolds using an evolved manganese catalyst and H2O2. The catalytic system provides structural complementarity to the substrate similarly to lock-and-key recognition in enzymatic active sites. Theoretical calculations reveal that enantioselectivity is determined by the precise fitting of the substrate scaffold into the catalytic site through a network of complementary weak non-covalent interactions. Stereoretentive C(sp(3))-H hydroxylation results in the generation of multiple stereogenic centers in a single step, which can be orthogonally manipulated to obtain a variety of chiral scaffolds from a single precursor molecule.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Marco Galeotti, Michela Salamone, Massimo Bietti
Summary: Direct functionalization of C(sp(3))-H bonds is a key focus in developing new synthetic methods. Among intermolecular C-H bond functionalization strategies, hydrogen atom transfer (HAT) methods using radical or radical-like reagents have gained increasing attention due to their ability to introduce a variety of atoms and groups in mild conditions. Selectivity control over aliphatic C-H bonds is crucial and factors influencing it have been discussed. This review article provides a detailed description of HAT reagents, associated mechanistic features, and selectivity patterns observed in the functionalization of increasingly complex substrates, based on an analysis of recent literature.
CHEMICAL SOCIETY REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Teo Martin, Michela Salamone, Massimo Bietti
CHEMICAL COMMUNICATIONS
(2019)