Article
Chemistry, Multidisciplinary
Joe Higham, James A. Bull
Summary: Transient directing groups (TDGs) combined with copper have been used for efficient C-H functionalization without additional steps for directing group introduction and removal. This method demonstrates high regioselectivity in the beta-C(sp(2))-H sulfonylation and gamma-(peri)-sulfonylation reactions of benzaldehydes and achieves through the use of catalytic beta-alanine and sulfinate salts, with copper fluoride serving as both the copper source and oxidant.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Qiangwei Li, Jiapian Huang, Zenghui Cao, Jun Zhang, Jie Wu
Summary: A photoredox-catalyzed three-component reaction was developed to access various arenesulfonohydrazides in moderate to good yields. The reaction exhibited broad substrate scope and excellent functional group compatibility under mild conditions, which was initiated by thianthrenium salts irradiation with visible light.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Mingda Li, Yangbin Jin, Yupeng Chen, Wanqing Wu, Huanfeng Jiang
Summary: This paper reports a new catalytic system for the efficient oxidative amination of unactivated olefins with primary aliphatic amines, leading to the formation of secondary allylic amines. The reaction proceeds through allylic C(sp3)-H activation and nucleophilic amination. The utility of this method is demonstrated in the late-stage modification and streamlined synthesis of drug molecules.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Applied
Hui-Min Jiang, Qing Sun, Jin-Peng Jiang, Jing-Hao Qin, Xuan-Hui Ouyang, Ren-Jie Song
Summary: We have described a method for the dicarbofunctionalization of alkenes, which allows for the introduction of alkyl and electron-rich aryl groups across the C=C bond of styrenes. This is achieved under copper catalyst and oxidative conditions, resulting in the construction of C(sp(3))-C(sp(2))/C(sp(3))-C(sp(3)) bonds via dual C-H functionalization. The method enables the synthesis of 1,1-diarylalkanes, which are important scaffolds found in natural products and drug molecules, by grafting electron-rich aromatics such as indoles, pyrroles, and trisubstituted aromatics.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Bryan C. Figula, Ting-An Chen, Jeffery A. Bertke, Timothy H. Warren
Summary: In this study, a radical relay C-H methylation method using a beta-diketiminate copper catalyst was developed, enabling the methylation of unactivated C(sp(3))-H bonds. By utilizing the bench-stable DABAL-Me-3 as a reagent, methylation of various substrates with both activated and unactivated C(sp(3))-H bonds was achieved with minimal overmethylation. Mechanistic studies suggested the involvement of a copper(II) methyl intermediate that reacts with methyl radicals and radicals R-center dot to form R-Me bonds.
Article
Chemistry, Physical
Manikantha Maraswami, Hajime Hirao, Teck-Peng Loh
Summary: This study achieved meta-arylation of phenols through copper catalysis with complete meta-selectivity and good tolerance towards various functional groups. Computational studies revealed that the reaction proceeded via a Heck-like pathway.
Article
Chemistry, Multidisciplinary
Youhao Wei, Zheng Wang, Kaifeng Wang, Jiang-Kai Qiu, Zhaoshan Wang, Haotian Li, Xiu Duan, Kai Guo, Xiaoguang Bao, Xinxin Wu
Summary: This study reports a copper-catalyzed allenic C(sp(2))-H cyanation with exceptional site-selectivity, addressing the challenge in synthetic chemistry of functionalizing allenic C(sp(2))-H bonds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Shibiao Tang, Xiaobo Zhao, Lidong Yang, Bin Li, Baiquan Wang
Summary: An efficient copper-catalyzed carboxylation of aryl thianthrenium salts with carbon dioxide at room temperature is developed, providing an effective method for the site-selective C-H carboxylation of aromatic hydrocarbons.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Yushi Tan, Wu Xuekun, Ya-Ping Han, Yuecheng Zhang, Hong-Yu Zhang, Jiquan Zhao
Summary: An efficient and convenient method for synthesizing 6-oxyalkylated 1,2,4-triazine-3,5(2H, 4H)-diones has been developed using a visible-light-induced cross-dehydrogenative coupling reaction. This reaction allows for a wide range of functional groups and uses a cheap and low-toxic photocatalyst and air as an oxidant. Additionally, the reaction can be driven by sunlight as a clean energy resource and has demonstrated utility in gram-scale reactions and the synthesis of key intermediates for bioactive molecules.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Amalia-Sofia Piticari, Daniele Antermite, Joe Higham, J. Harry Moore, Matthew P. Webster, James A. Bull
Summary: This study achieved the selective Pd-catalyzed C-H cis-functionalization of piperidine and tetrahydropyran carboxylic acids using a C(4) aminoquinoline amide auxiliary. High mono- and cis-selectivity was obtained by adding mesityl carboxylic acid. The reaction conditions developed in this study had significantly lower temperatures compared to other reported heterocycle C(sp(3))-H functionalization reactions, and a one-pot C-H functionalization-epimerization procedure was established to directly obtain the trans-3,4-disubstituted isomers. Diverse aminoquinoline removals were achieved by installing carboxylic acid, alcohol, amide, and nitrile functional groups. Overall, fragment compounds suitable for screening were synthesized in 3-4 steps from readily-available heterocyclic carboxylic acids.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Jiangcheng Xu, Yun Zhang, Jiale Han, An Su, Haoran Qiao, Chengyun Zhang, Jing Tang, Xi Shen, Bin Sun, Wenbo Yu, Silong Zhai, Xinqiao Wang, Yejian Wu, Weike Su, Hongliang Duan
Summary: In this study, a Transformer model was used to predict the structures and stereochemistry of key intermediates in organic reactions, addressing the challenge of predicting reaction mechanisms. By defining key intermediates and fine-tuning the model, remarkable accuracy and interpretability were achieved. This research provides a novel approach for chemists to discover reaction mechanisms.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Zhi-Jiang Jiang, Si-Han Xu, Yuhang Su, Erxun Hu, Jiawei Han, Jian-Fei Bai, Bencan Tang, Jia Chen, Zhanghua Gao
Summary: A nickel-catalyzed hydrogen isotope exchange has been developed using acetone-d6 as the deuterium source. With the assistance of 2-pyridones, the reaction exhibits improved kinetic features of H/D exchange, leading to the efficient synthesis of regioselective labeled aryl and alkyl carboxamides.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Chen Li, Bin Chen, Xiaodong Ma, Xueling Mo, Guozhu Zhang
Summary: A catalytic asymmetric alkylation of azoles with secondary 1-arylalkyl bromides through direct C-H functionalization was reported. The reaction, under blue-light photoexcitation, showed good reactivity and high stereoselectivity, providing an efficient strategy for the construction of chiral alkyl azoles at low temperature. The reactions are compatible with a wide range of azoles.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Xiaodong Ma, Guozhu Zhang
Summary: This study describes a copper-catalyzed, highly enantioselective alkyl and aryl/azolation of alkenes, where the use of a specific chiral ligand plays a crucial role in the success of the chemistry. Anionic tridentate ligands are employed to enhance the reducibility of copper complexes, facilitating the generation of alkyl/aryl radicals and providing good enantiocontrol in the azolation. The three-component coupling reactions have mild reaction conditions and can tolerate a broad range of functional groups, allowing for the straightforward introduction of valuable azole functionalities into complex molecular systems through direct C-H functionalization.
Article
Chemistry, Multidisciplinary
Kritika Laxmikeshav, Akash P. Sakla, Stephy Elza John, Nagula Shankaraiah
Summary: A facile and proficient dithiocarbamation of imidazo[1,2-a]pyridines and other imidazoheterocycles is established using a copper(i) catalyst and molecular oxygen under microwave conditions, resulting in moderate to excellent yields. The synthesized derivatives have drug-like properties and good ADME/T profile, with compounds 3be and 3bb showing more potency towards MCF-7 human breast cancer cells compared to the standard drug 5-fluorouracil.
Article
Chemistry, Analytical
Roman Picazo-Frutos, Quentin Stern, John W. Blanchard, Olivier Cala, Morgan Ceillier, Samuel F. Cousin, James Eills, Stuart J. Elliott, Sami Jannin, Dmitry Budker
Summary: Zero- to ultralow-field nuclear magnetic resonance is a magnetic resonance experiment that does not require strong superconducting magnets. It allows high-resolution detection of nuclear magnetism through metal and within heterogeneous media. By using dissolution dynamic nuclear polarization, signals in zero-field nuclear magnetic resonance experiments can be enhanced on sample mixtures, and this technique can be applied to a wide range of molecules. The signal enhancements can reach up to 11,000 compared to thermal prepolarization in a 2 T permanent magnet. The relaxation effects of the TEMPOL radicals used in the hyperpolarization process at zero- and ultralow-fields are also investigated to further increase the signal in future experiments.
ANALYTICAL CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
James Eills, Dmitry Budker, Silvia Cavagnero, Eduard Y. Chekmenev, Stuart J. Elliott, Sami Jannin, Anne Lesage, Joerg Matysik, Thomas Meersmann, Thomas Prisner, Jeffrey A. Reimer, Hanming Yang, Igor V. Koptyug
Summary: Magnetic resonance techniques, especially medical magnetic resonance imaging, are widely used in various scientific disciplines and practical applications. The development of spin hyperpolarization has greatly boosted both fundamental and applied magnetic resonance. Hyperpolarization techniques significantly enhance the signal intensity of magnetic resonance, overcoming its low sensitivity and opening up new possibilities for applications.
Article
Chemistry, Organic
Xi Zhao, Xiaofeng Yu, Mingjun Liu, Yanping Huo, Shaomin Ji, Xianwei Li, Qian Chen
Summary: An efficient synthesis of 9-benzylated fluorenols with high atom economy (<= 91% yield) has been achieved through an external photocatalyst-free benzylic C-H functional-ization using fluorenones under visible-light irradiation. Spectroscopic studies suggest that the photoexcited fluorenones undergo a reductive quenching with toluene derivatives to generate ketyl radicals and benzyl radicals, which then undergo a cross-coupling reaction to yield the desired fluorenols.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Applied
Bairong Liu, Yabo Chen, Qixin Liang, Yuyao Liang, Bifu Liu, Yuan Liu, Yang Gao, Qian Chen, Yanping Huo, Xianwei Li
Summary: Regiodivergent [3+2] and [4+2] C-H annulation of imines and imidate esters with unsymmetrical alkynes has been achieved under Rh(III) catalysis. Further transformation of the aldehyde and TMS functionality on the indene products is also demonstrated. The current work highlights the alcohols-directed multiple C-H annulation of imines and imidate esters, leading to diverse fused heterocycles.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Physics, Multidisciplinary
Kai Wei, Tian Zhao, Xiujie Fang, Zitong Xu, Chang Liu, Qian Cao, Arne Wickenbrock, Yanhui Hu, Wei Ji, Jiancheng Fang, Dmitry Budker
Summary: Achieving high energy resolution in spin systems is important for fundamental physics research and precision measurements. We found a new relaxation mechanism in alkali-noble-gas comagnetometers and demonstrated a tenfold increase in nuclear spin hyperpolarization and coherence time with optimal hybrid optical pumping. Our proposed use of this comagnetometer can surpass previous limits in searching for exotic spin-dependent interactions.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Rui Zhang, Dimitra Kanta, Arne Wickenbrock, Hong Guo, Dmitry Budker
Summary: We present an alignment-based 87Rb magnetometer that overcomes the issue of nonlinear Zeeman splitting in alkali-metal atomic magnetometry. The magnetometer exhibits immunity to NLZ-related errors due to a single magnetic resonance peak and well-separated hyperfine transition frequencies. Experimental results show that the magnetometer can be used for practical measurements in geomagnetic environments, achieving a photon-shot-noise-limited sensitivity of 9 fT/pat 5 mu T and remaining stable at tens of fT/ ffiffiffiffiffiffiffiffiffiffiHz p at Hz 50 mu T at room temperature.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Xue Zhang, Abhishek Banerjee, Mahapan Leyser, Gilad Perez, Stephan Schiller, Dmitry Budker, Dionysios Antypas
Summary: The effects of scalar and pseudoscalar ultralight bosonic dark matter were investigated using quartz oscillator frequencies and atomic transitions. Linear interactions were constrained for scalar dark matter in the mass range of 1 x 10-17-8.3 x 10-13 eV, and quadratic interactions were constrained for pseudoscalar dark matter in the mass range of 5 x 10-18-4.1 x 10-13 eV. These constraints improve upon previous direct searches and astrophysical observations.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Atomic, Molecular & Chemical
Danila A. Barskiy, John W. Blanchard, Dmitry Budker, Quentin Stern, James Eills, Stuart J. Elliott, Roman Picazo-Frutos, Antoine Garcon, Sami Jannin, Igor V. Koptyug
Summary: The combination of nuclear hyperpolarization technique with (near-)zero-field modalities has great potential in various applications of nuclear magnetic resonance spectroscopy and imaging, such as biomedical diagnostics and monitoring catalytic reactions in metal reactors.
APPLIED MAGNETIC RESONANCE
(2023)
Article
Chemistry, Organic
Yupeng Zhao, Yang Gao, Zhongke Xie, Shuwei Liao, Jiebin Huang, Yanping Huo, Qian Chen, Xianwei Li, Xiao-Qiang Hu
Summary: Different chemoselectivities were observed between phenols and thiophenols in the Tf2O-promoted C3 functionalization of simple anthranils. Phenols and anthranils react to form 3-aryl anthranils via a C-C bond formation, while thiophenols form 3-thio anthranils through a C-S bond formation. Both reactions have a broad substrate scope and tolerate a wide range of functional groups, yielding the corresponding products with specific chemoselectivity.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Quantum Science & Technology
Jabir Chathanathil, Dmitry Budker, Svetlana A. Malinovskaya
Summary: A chirped-pulse quantum control scheme called C-CARS is proposed for enhancing the vibrational coherence in molecules during coherent anti-Stokes Raman scattering spectroscopy. The scheme involves chirping of the pump, Stokes, and probe pulses in the four-wave mixing process of CARS to satisfy the conditions of adiabatic passage. By utilizing the rotating wave approximation and adiabatic elimination of excited state manifold, the four-level model system is simplified into a "super-effective" two-level system. It is demonstrated that the excitation selectivity of vibrational degrees of freedom can be controlled by adjusting the spectral chirp rate of the pulses. The robustness, spectral selectivity, and adiabatic nature of this method make it advantageous for improving CARS spectroscopy for sensing, imaging, and detection purposes.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Derek F. Jackson Kimball, Dmitry Budker, Timothy E. Chupp, Andrew A. Geraci, Shimon Kolkowitz, Jaideep T. Singh, Alexander O. Sushkov
Summary: This article surveys the applications of spin-based quantum sensors in measurements probing fundamental physics. Experimental methods and technologies developed for spin-based quantum information science have rapidly advanced, enabling precise control and measurement of spin dynamics. Theories beyond the standard model predict phenomena such as discrete-symmetry-violating electromagnetic moments correlated with particle spins, exotic spin-dependent forces, and coupling of spins to ultralight bosonic dark-matter fields. Spin-based quantum sensors provide a methodology complementary to particle colliders and large-scale particle detectors, offering a way to search for these phenomena and test fundamental physics. The article also highlights areas of technological development that can enhance the sensitivity of spin-based quantum sensors to new physics.
Article
Chemistry, Multidisciplinary
James Eills, Roman Picazo-Frutos, Dudari B. B. Burueva, Larisa M. M. Kovtunova, Marc Azagra, Irene Marco-Rius, Dmitry Budker, Igor V. V. Koptyug
Summary: We demonstrate a catalyst-free approach to produce hyperpolarized [1-C-13]succinate in aqueous solutions, utilizing parahydrogen-induced polarization (PHIP) and a combination of homogeneous and heterogeneous catalytic hydrogenation reactions. A homogeneous ruthenium catalyst and para-enriched hydrogen gas are employed for PHIP to generate hyperpolarized [1-C-13]fumarate, followed by the removal of the toxic catalyst and reaction side products through a purification procedure. A second hydrogenation reaction is carried out using normal hydrogen gas and a solid Pd/Al2O3 catalyst to convert fumarate to succinate. This cost-effective method has a turnover time of a few minutes and represents a significant breakthrough for in vivo applications of hyperpolarized [1-C-13]succinate as a contrast agent.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Yuanting Huang, Jinyu Tang, Xi Zhao, Yanping Huo, Yang Gao, Xianwei Li, Qian Chen
Summary: The development of P(O)-heteroatom bond-forming reactions is crucial, but previous methods have limitations. This study presents an efficient and green photocatalytic phosphorylation of heteroatom nucleophiles utilizing acid red 51 as the photocatalyst and air as the oxidant under blue LED irradiation. The reaction exhibits broad substrate scope and provides practical access to phosphinic fluorides, phosphinic amides, phosphoramidates, and phosphinates. Mechanistic studies suggest the involvement of a phosphorus-centered radical cation generated by photocatalytic single electron transfer (SET).
Article
Astronomy & Astrophysics
I. M. Bloch, D. Budker, V. V. Flambaum, I. B. Samsonov, A. O. Sushkov, O. Tretiak
Summary: Scalar-field dark matter models suggest small oscillations of fundamental constants, which could lead to observable variations in the magnetic field of a permanent magnet. We propose an experiment using a SQUID magnetometer or a low-noise radiofrequency amplifier to detect this type of dark matter. Our results show that this experiment may have comparable sensitivity to leading experiments searching for variations of fundamental constants in a frequency range from a few Hz to about 1 MHz. We also discuss the applicability of using variations of fundamental constants to account for the interaction with scalar dark matter.
Article
Chemistry, Organic
Bairong Liu, Jianhang Rao, Weibing Liu, Yang Gao, Yanping Huo, Qian Chen, Xianwei Li
Summary: By tuning the divergent oxidative Heck reaction with O-2 enabled by self-assembled imines, olefins achieved site selectivity and stereoselectivity. The compatibility of strongly coordinating pyridines and quinolines facilitated the concise delivery of selective serotonin 4 receptor ligand, topotecan, and irinotecan analogues.
ORGANIC CHEMISTRY FRONTIERS
(2023)