Article
Chemistry, Physical
Jurin Kanarat, Thanthapatra Bunchuay, Wantana Klysubun, Jonggol Tantirungrotechai
Summary: Chitosan is utilized as a macrochelating ligand for metal active species, while copper oxide-chitosan composites exhibit efficient catalytic performance in the C-H oxidation of alkylarene. The composites have high activity, selectivity, and can convert a wide range of substrates to corresponding ketones with good yields.
Article
Chemistry, Multidisciplinary
Ling Dai, Ying-Ying Chen, Li-Jun Xiao, Qi-Lin Zhou
Summary: Intramolecular enantioselective radical C(sp(3))-H functionalization allows for the synthesis of chiral amines, but methods for intermolecular enantioselective C(sp(3))-H amination remain elusive. Here, a cationic copper catalytic system for intermolecular enantioselective benzylic C(sp(3))-H amination with peroxide as an oxidant is reported. This method allows for the transformation of various alkylarenes and amides into chiral amines with high enantioselectivities and has good functional group tolerance and broad substrate scope. Moreover, it can be used to synthesize bioactive molecules, including chiral drugs.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Louis Kimberley, Alena M. Sheveleva, Jiangnan Li, Joseph H. Carter, Xinchen Kang, Gemma L. Smith, Xue Han, Sarah J. Day, Chiu C. Tang, Floriana Tuna, Eric J. L. McInnes, Sihai Yang, Martin Schroder
Summary: This study presents an efficient method for oxidizing benzylic C-H groups using the metal-organic framework material MFM-170, which can be applied to a wide range of substrates under mild conditions. Comprehensive investigations utilizing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X-ray diffraction have identified the critical role of the paddlewheel moiety in activating the oxidant.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Zhong-Wei Hou, Ding-Jin Liu, Peng Xiong, Xiao-Li Lai, Jinshuai Song, Hai-Chao Xu
Summary: This study reports a site-selective electrochemical amination reaction that can convert benzylic C-H bonds into C-N linkages without the need for external oxidants or metal catalysts. The success lies in using HFIP as a co-solvent to modulate the oxidation potentials of the substrate and product, avoiding overoxidation of the latter.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Zhong-Wei Hou, Laiqiang Li, Lei Wang
Summary: An organocatalytic site-selective electrochemical method has been developed for the benzylic C-H amination reactions of alkylarenes with azoles through hydrogen evolution. The protocol uses 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a redox catalyst to generate carbocations, eliminating the need for transition-metal reagents or sacrificial chemical oxidants.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Pin Xu, Wenzheng Fan, Pinhong Chen, Guosheng Liu
Summary: The first enantioselective radical trifluoromethylation of benzylic C-H bonds has been achieved using a cooperative photoredox and copper catalysis system. This method provides straightforward access to structurally diverse benzylic trifluoromethylation products with excellent enantioselectivities under mild conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Nanoscience & Nanotechnology
Neelam Gupta, Hiren K. Machhi, Bhumi A. Baraiya, Saurabh S. Soni, Ashutosh Bedekar, Prafulla K. Jha, Hemant P. Soni
Summary: Octahedral-shaped Cu2O nanocrystals were synthesized and used as catalyst for benzylic sp(3) C-H bond oxidation. The oxidation of Cu2O to CuO can be avoided in the dark or inert atmosphere or continuous flow of oxygen gas. The proposed reaction mechanism involves activation of O-2 molecule through single electron transfer (SET) mechanism on the (111) facets of semiconducting Cu2O NCs in light.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Physical
Ruixue Zhang, Yan Chen, Muhua Ding, Jie Zhao
Summary: This review provides a comprehensive summary of seminal heterogenized Cu-catalyzed homogenous catalysis reported over the last decade, highlighting the potential and synthetic perspectives of heterogeneous copper catalysis in both academic and industry.
Article
Chemistry, Applied
Niklas R. R. Bennedsen, Faliu Yang, Farnoosh Goodarzi, Soren Kramer, Soren Kegnaes
Summary: Organoboron compounds play a crucial role in the synthesis of pharmaceutical and agricultural compounds through various key transformations. Direct C-H borylation has advantages over traditional halide-based transformations by reducing stoichiometric waste. This study focuses on developing heterogeneous catalysts based on porous organic polymers (POPs) for more sustainable and recyclable borylation reactions. The results show that the synthesized POPs, when ligated with metal ions, exhibit efficient borylation activity and can be recycled multiple times.
TOPICS IN CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Jiami Guo, Zi-An Shen, Xueting Zhou, Lei Dai, Yixin Lu
Summary: In this study, we achieved highly enantioselective functionalization of substrates bearing a benzylic C-H bond through photo-induced activation of ortho-alkyl aromatic ketones. Using amino acid-derived bifunctional phosphine catalysts, a range of benzylic allylation products were obtained in good yields and with excellent enantioselectivities. This research provides new insights into the activation and functionalization of pronucleophiles containing less acidic C-H bonds in the domain of phosphine catalysis and beyond.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Organic
Mikkel B. Buendia, Jan-Georges J. Balin, Mette E. Andersen, Zhong Lian, Soren Kramer
Summary: A simple method for copper-catalyzed benzylic C-H alkynylation using alkynylboronic esters as nucleophilic coupling partners is reported. The catalytic system is readily available and reactions occur under mild conditions. Different substrates and alkynylboronic ester nucleophiles were evaluated, and enantioselective C-H alkynylations were also demonstrated in three examples.
Article
Chemistry, Multidisciplinary
Kyle J. Korman, Michael R. Dworzak, Glenn P. A. Yap, Eric D. Bloch
Summary: This paper describes the preparation of a new class of reactive porous solids through straightforward salt metathesis reactions. A porous solid is obtained by reacting the dimethylammonium salt of a magnesium-based porous coordination cage with the chloride salt of [(CrCl)-Cl-II(Me(4)cyclam)](+), with simultaneous removal of dimethylammonium chloride. The porous salt exhibits a Brunauer-Emmett-Teller (BET) surface area of 213 m(2) g(-1) and the chromium(II) cations in the structure are still accessible and reactive, as confirmed by UV-vis spectroscopy. The site-isolated reactive centers show enhanced stability and reactivity compared to dissolved ions.
Article
Chemistry, Physical
Mickael Henrion, Yorck Mohr, Kwinten Janssens, Simon Smolders, Aram L. Bugaev, Oleg A. Usoltsev, Elsje Alessandra Quadrelli, Florian M. Wisser, Dirk E. De Vos, Jerome Canivet
Summary: New catechol-based porous polymers were synthesized and used as platforms for the heterogenization of molecular Cu complexes. The resulting Cu@CatMP-1 materials proved to be highly stable and performing catalysts with turnover numbers up to 6000, about 1 to 2 orders of magnitude higher than the current relevant state of the art. The solid catalyst showed recyclability for over 10 runs without metal leaching and has been scaled to the gram scale. The coordination of Cu to catechol within the polymer has been confirmed by X-ray absorption spectroscopy.
Article
Chemistry, Multidisciplinary
Shutao Sun, Yingang Ma, Ziqiang Liu, Lei Liu
Summary: A novel manganese-catalyzed oxidative kinetic resolution method was reported, which effectively reacts asymmetric C(sp(3))-H oxidation to distinguish different types of cyclic benzylic ethers with wide application prospects and high enantiodiscrimination efficiency. This study further explores the direct late-stage oxidative kinetic resolution of bioactive molecules that are otherwise difficult to access.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Mohammad Bayatani, Morteza Torabi, Meysam Yarie, Mohammad Ali Zolfigol, Zahra Farajzadeh
Summary: This study reports the post modification of the imidazole units in the porous organic polymer (POP) to synthesize a magnetic ionic POP called Im-MIPOP. The Im-MIPOP is used as a heterogeneous catalytic system in the Betti reaction, showing high yields (up to 93%), short reaction times, and acceptable recyclability.
JOURNAL OF MOLECULAR LIQUIDS
(2023)