Article
Chemistry, Multidisciplinary
Jun Chen, Yu-Jie Liang, Peng-Zi Wang, Guo-Qing Li, Bin Zhang, Hao Qian, Xiao-Die Huan, Wei Guan, Wen-Jing Xiao, Jia-Rong Chen
Summary: This study presents a photoinduced copper-catalyzed cross-coupling reaction for the generation of allylic esters. The reaction proceeds at room temperature with high regio- and enantioselectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Yanhui Wang, Xiaotian Qi, Qiao Ma, Peng Liu, Gavin Chit Tsui
Summary: The diastereoselective synthesis of densely functionalized tetrasubstituted (E)-monofluoroalkenes via Pd(0)-catalyzed base-free Suzuki-Miyaura crosscouplings offers a significant method for producing pharmaceutically relevant compounds. Computational studies support the reaction design, revealing an intriguing mechanism of C-F bond activation leading to complete control of stereoselectivity. This method does not require extraneous base assistance, making it a powerful tool for stereocontrolled synthesis of monofluoroalkenes.
Article
Chemistry, Organic
Xian Xu, Qianlin Sun, Xin Xu
Summary: This work presents a chemo- and stereoselective benzylic C(sp(3))-H alkenylation of tertiary ortho-methyl anilines with internal alkynes using a beta-diketiminato scandium catalyst. The protocol offers an efficient method for synthesizing a new family of tertiary ortho-allylanilines in high yields, which can be further transformed into other valuable anilines. A cationic scandium benzyl species was identified as the catalytic intermediate.
Editorial Material
Chemistry, Multidisciplinary
Yi Wei, Fen-Ya Xiong, Liang-Qiu Lu, Wen-Jing Xiao
Summary: In this paper, Gevorgyan et al. described a photoinduced palladium catalysis method that enables the direct allylic C-H amination of alkenes, including internal ones. This strategy overcomes a major challenge in chemical synthesis and offers excellent selectivities.
Article
Chemistry, Organic
Anton S. Makarov, Arthur N. Bakiev, Diana A. Eshmemeteva
Summary: We present a metal- and additive-free method for synthesizing meta-substituted anilines using commercially available or one-step accessible substituted methylvinyl ketones, N-acylpyridinium salts, and primary/secondary alkyl- and arylamines. This method enables the synthesis of anilines with uncommon substitution patterns and has potential applications in medicinal chemistry and materials science.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Nan-Quan Jiang, Tian-Shu Wu, Min Pan, Zhong-Jian Cai, Shun-Jun Ji
Summary: A novel palladium-catalyzed regioselective diarylation/deamination of homoallylamines is described, where a free amine is used as the directing group and removed in situ to form a unique tetraarylbutadiene motif. This chelate-controlled Heck-type approach eliminates the need for preinstalled and hard removable directing groups, proceeds under simple conditions, and exhibits good tolerance to a wide range of functional groups commonly found in organic synthesis.
Article
Chemistry, Organic
Gautam Kumar, Zheng-Wang Qu, Stefan Grimme, Indranil Chatterjee
Summary: Catalytic hydroarylation reactions of conjugated dienes using tris(pentafluorophenyl)borane as a Lewis acid catalyst show a broad substrate scope for highly regioselective functionalization of sterically hindered aniline derivatives. Experimental and theoretical studies reveal the crucial role of residual water and B(C6F5)(3) complex in the reaction mechanism.
Article
Chemistry, Multidisciplinary
Balaji D. Barve, Yao-Haur Kuo, Wen-Tai Li
Summary: The use of bulky ligands can enhance the reductive elimination pathway and inhibit beta-hydride elimination, leading to the selective formation of difunctionalized alkene products.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Yuzhou Wang, Rongrong Xie, Lingyu Huang, Ya-Nan Tian, Shihai Lv, Xiangfei Kong, Shiqing Li
Summary: An efficient metal-catalyzed tandem reaction was developed for the synthesis of unsymmetrical azobenzenes, eliminating the need for extra deprotection steps. Additionally, a novel three-component reaction process was discovered to assemble azobenzenes in good yields.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Sinem Guven, Gourab Kundu, Andrea Wessels, Jas S. Ward, Kari Rissanen, Franziska Schoenebeck
Summary: In this study, a remote functionalization strategy was reported for the Z-selective synthesis of silyl enol ethers of (hetero)aromatic and aliphatic ketones via Ni-catalyzed chain walking. The positional selectivity is controlled by the directionality of the chain walk, independent of the resulting silyl enol ether's thermodynamic preferences. Mechanistic data indicate the formation of a Ni-(I) dimer under these conditions, which serves as a catalyst resting state and converts to an active chain-walking/functionalization catalyst, ultimately generating a stabilized eta(3)-bound Ni-(II) enolate as the key selectivity-controlling intermediate.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Yang Gao, Yushan Cui, Yanping Huo, Jinhong Chen, Minwei She, Xianwei Li, Qian Chen, Xiao-Qiang Hu
Summary: A nickel-catalyzed polarity-reversed hydroamination of olefins has been developed, providing a convenient route to N-alkyl-2-aminobenzophenones intermediates. This method is compatible with a wide range of olefins and anthranils, delivering the desired amines in high yields, making it applicable for organic synthesis.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yin-Long Lai, Shaoxi Yan, Dan He, Li-Zhen Zhou, Zi-Shen Chen, Yu-Long Du, Jianxiao Li
Summary: This study introduces an efficient palladium-catalyzed three-component cascade bisthiolation method using sodium thiosulfate as the sulfur source for the synthesis of functionalized (Z)-1,2-bis(arylthio)alkene derivatives. The catalyst IPr-Pd-Im-Cl-2 showed good tolerance towards a wide range of terminal alkynes and arylhydrazines, leading to high yields and excellent regioselectivity in the desired products. Furthermore, the protocol is scalable and shows potential applications in organic synthesis and material science.
Article
Chemistry, Organic
Jun-Bin Tang, Jun-Qian Bian, Yu-Shuai Zhang, Yong-Feng Cheng, Han-Tao Wen, Zhang-Long Yu, Zhong-Liang Li, Qiang-Shuai Gu, Guo-Qiang Chen, Xin-Yuan Liu
Summary: A copper-catalyzed highly anti-selective radical 1,2-alkylarylation of terminal alkynes has been established, providing facile access to various stereo-defined trisubstituted alkenes in high yield under mild reaction conditions.
Article
Chemistry, Multidisciplinary
Gyumin Kang, Sunkyu Han
Summary: In this study, we successfully synthesized dimeric high-oxidation-state securinega alkaloid Flueggeacosine B via two synthetic routes. The second-generation synthesis was more streamlined and a new reaction was developed to provide a direct pathway for the synthesis of compounds with a conjugated dicarbonyl moiety.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Yin-Long Lai, Shao-Xi Yan, Sheng-Ling Zhang, Yu-Hong Huang, Ru-Xin Hu, Yang-Chong Chen, Jian-Min Luo, Jianxiao Li
Summary: A reliable and efficient palladium-catalyzed cascade cyclization/alkylation reaction of oxime ethers with unactivated alkenes is reported, yielding a variety of structurally diverse isoxazole derivatives in moderate to good yields with excellent functional group compatibility. Ionic liquid [Aeim]Br serves as an environmentally friendly solvent and an accelerating agent, providing excess bromine source to eliminate bromomethane from oxime ethers. Moreover, the use of chain-walking strategy enables rapid generation of molecular complexity from readily available starting materials in organic synthesis.
CHEMISTRY-AN ASIAN JOURNAL
(2022)
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)
Review
Biochemistry & Molecular Biology
Pu Chen, Huawen Huang, Qi Tan, Xiaochen Ji, Feng Zhao
Summary: The synthetic strategies of oxime derivatives participating in radical-type reactions have been rapidly developed in the last few decades. The N-O bond cleavage of oxime esters leading to the formation of nitrogen-centered radicals triggers adjacent C-C bond cleavage to produce carbon-centered free radicals, which has been virtually used in organic synthesis in recent years. In this review, the free radical reactions involving acyl oxime esters and cyclic ketoxime esters after 2021 were included, with emphasis on the substrate scope and reaction mechanism.
Article
Chemistry, Organic
Ning Xian, Jiang Yin, Xiaochen Ji, Guo-Jun Deng, Huawen Huang
Summary: The visible-light-induced photoredox carbon radical formation from aqueous sulfoxonium ylides has been demonstrated for the first time. Direct reduction of sulfoxonium ylides by H2O generates hydrocarbon compounds efficiently, while the use of additional alkenes as radical acceptors changes the chemical reactivity to achieve alkene carboarylation of N-arylacrylamides. Mechanistic studies reveal two different reaction pathways involved in the carbon radical formation from aqueous sulfoxonium ylides resulting in reduction to release dimethyl sulfone and carboarylation to form DMSO.
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
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
Chemistry, Organic
Xinzhuang Wu, Xinyi Zhang, Xiaochen Ji, Guo-Jun Deng, Huawen Huang
Summary: A cascade arylazidation reaction of activated alkenes with trimethylsilyl azide (TMSN3) under visible-light irradiation has been developed. Mechanistic investigations reveal that the reaction proceeds via single electron transfer (SET) between TMSN3 and the excited photocatalyst, followed by radical addition/aryl migration/desulfonylation to yield valuable α-aryl-β-azido amides and azidated oxindoles as versatile building blocks in organic synthesis. The obtained arylazidated products can be further converted to valuable β-amino amide and 1,2,3-triazole derivatives with simple treatment.
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).
