Article
Chemistry, Multidisciplinary
Xuan Yu, Zining Zhang, Guangbin Dong
Summary: This study presents the discovery of a Rh-catalyzed enantioselective C-C activation involving migration of a sulfonyl radical. This unusual process transforms cyclobutanones containing a sulfonamide-tethered 1,3-diene moiety into gamma-lactams containing a beta-quaternary center with excellent enantioselectivity. The reaction exhibits broad functional group tolerance and a good substrate scope.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
David N. Stephens, Robert K. Szilagyi, Paige N. Roehling, Navamoney Arulsamy, Michael T. Mock
Summary: We have reported a nickel complex that can catalyze the oxidation of ammonia to dinitrogen under ambient conditions. By using aryloxyl or N-oxyl radicals as H atom acceptors, the N-H bonds of coordinated NH3 ligands can be cleaved to generate N-2 molecules. Isotopic nitrogen studies have identified a bridging Ni-hydrazine product, supported by computational models, indicating a bimetallic homocoupling mechanism for N-N bond formation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Ziqi Zhang, Jianyan Wang, Mengxia Yu, Shengqing Ye, Jie Wu
Summary: A three-component reaction of alkenyl-tethered oxime ethers, sodium metabisulfite, and aryldiazonium tetrafluoroborates has been developed under mild conditions. This reaction proceeds at room temperature without any oxidants or additives, leading to the formation of fi-amino sulfones with good functional group tolerance through aminosulfonylation of unactivated alkene. Mechanistic studies have revealed that this transformation involves a radical process, including radical trapping with sulfur dioxide and radical 1,4-amino migration.
Article
Chemistry, Multidisciplinary
Tao Qin, Guowei Lv, Qi Meng, Ge Zhang, Tao Xiong, Qian Zhang
Summary: An efficient and general radical hydroamination of alkenes has been achieved using Co(salen) as catalyst, NFSI and its analogues as both nitrogen source and oxidant. Mechanistic experiments indicate that the reaction proceeds through a metal-hydride-mediated hydrogen atom transfer and a catalyst-controlled S(N)2-like pathway. Additionally, an unprecedented asymmetric version with good to excellent enantiocontrol was accomplished using a modified chiral cobalt(II)-salen catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Mayukh Bhadra, Wesley J. Transue, Hyeongtaek Lim, Ryan E. Cowley, Jung Yoon C. Lee, Maxime A. Siegler, Patrick Josephs, Gerald Henkel, Markus Lerch, Siegfried Schindler, Adam Neuba, Keith O. Hodgson, Britt Hedman, Edward Solomon, Kenneth D. Karlin
Summary: This study focused on the central role of cupric superoxide intermediates in hormone and neurotransmitter biosynthesis, investigating the impact on enzyme characteristics. A model of cupric superoxide and its reactivity were described, shedding light on the O-2-binding behavior and redox activity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Yao Luo, Qi Wei, Liangkun Yang, Yuqiao Zhou, Weidi Cao, Zhishan Su, Xiaohua Liu, Xiaoming Feng
Summary: The synthesis of chiral ketones has been a significant focus in chemistry research. In this study, researchers successfully achieved a highly selective radical hydroacylation reaction for α-substituted α,β-unsaturated carbonyl compounds using anthraquinone photocatalyst and chiral N,N'-dioxide/metal complexes. This method provides a mild and robust approach to access a wide range of chiral ketones with α-tertiary stereocenters.
Article
Engineering, Environmental
Penghui Du, Junjian Wang, Guodong Sun, Long Chen, Wen Liu
Summary: This study elucidated the reaction mechanism of the acetylperoxyl radical (CH3CO3 center dot)-driven oxidation of phenol. The results showed that hydrogen atom abstraction (HAA) is the most favorable route in the initial step of CH3CO3 center dot-driven phenol oxidation. The generated phenoxy radicals further undergo dimerization or react with CH3CO3 center dot to produce different products.
Article
Chemistry, Multidisciplinary
Youqing Yang, Constantin G. Daniliuc, Armido Studer
Summary: A radical 1,1,2-trifunctionalization of terminal alkynes is achieved using alkyl triflones as precursors and trapping reagents, with good yields of highly substituted cyclopentanes obtained at elevated temperatures using dibenzoyl peroxide or alpha,alpha '-azobisisobutyronitrile as initiators.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Xin Nie, Chen-Xi Ye, Sergei I. Ivlev, Eric Meggers
Summary: A new synthetic method for the preparation of non-racemic 5-membered cyclic carbonates from abundant alcohols has been reported. The conversion of the alcohol into an azanyl carbonate, followed by a chiral-at-ruthenium catalyzed cyclization, resulted in chiral cyclic carbonates with yields of up to 95% and enantiomeric excess (ee) of up to 99%. This method involves a nitrene-mediated intramolecular C(sp(3))-H oxygenation, which includes an unusual 1,7-hydrogen atom transfer within a ruthenium nitrene intermediate.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Zhikun Wu, Xiying Zhang, Nian Xu, Xiaohua Liu, Xiaoming Feng
Summary: The breakthrough in diastereo- and enantioselective catalytic aerobic oxidative radical addition/hydroxylation/1,4-aryl migration processes from bisaryl-substituted ethenes and indanone derivatives was achieved by combining CuI/O-2 oxidative system and chiral Lewis acid-involved asymmetric catalysis. The aerobic oxidative addition provided a straightforward and in situ generation of diaryl alcohol and distal radical for 1,4-aryl migration. An easily available chiral magnesium complex catalyst could relay chiral information in radical addition and 1,4-aryl migration with high diastereo- and enantioselectivity.
Article
Chemistry, Multidisciplinary
Xin Chang, Xiang Cheng, Xue-Tao Liu, Cong Fu, Wei-Yi Wang, Chun-Jiang Wang
Summary: An unprecedented hydroalkylation reaction catalyzed by Cu/Ru relay was developed, merging the ruthenium-catalyzed asymmetric borrowing-hydrogen reaction with a copper-catalyzed asymmetric Michael addition. This method enables the efficient preparation of highly functionalized delta-hydroxyesters bearing 1,4-nonadjacent stereocenters with high levels of diastereoselectivity and excellent enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Shunya Ohuchi, Hiroki Koyama, Hiroki Shigehisa
Summary: A catalytic synthetic method for cyclic guanidines was developed via transition-metal hydrogen atom transfer and radical-polar crossover, enabling the formation of five-, six-, and seven-membered rings with common protective groups on alkenyl guanidines. The derivatization of the products afforded various heterocycles, showing the versatility of this powerful method for generating diverse compounds. Selective cyclization and further derivatizations of mono- or heteroprotected alkenyl guanidines were also investigated in this study.
Article
Chemistry, Organic
Chun-Hong Hu, Yang Li
Summary: A metal-free synthesis of C1-deuterated aldehydes was developed, which utilizes D2O and alpha-oxo carboxylic acids at ambient temperature. This method avoids the use of stoichiometric reductants and oxidants, and can tolerate various functional groups, resulting in high yields and high deuteration levels.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Shengqing Zhu, Xian Zhao, Huan Li, Lingling Chu
Summary: The merging of nickel catalysis with radical chemistry has provided a new and benign platform for the catalytic dicarbofunctionalization of unsaturated pi bonds with unprecedented reactivity and selectivity. Recent advances in this area mainly involve catalytic domino transformations and exploration of reaction mechanisms.
CHEMICAL SOCIETY REVIEWS
(2021)
Review
Chemistry, Applied
Rui-Lin Zhang, Kai-Xiong Qiu, Hong-Fei Gao, Fang Yu, Zhong-Wen Sun
Summary: This review summarizes the importance of catalytic asymmetric reactions of benzoxazinone derivatives in obtaining chiral aza-heterocycles, which are key frameworks in natural products. It showcases the potential and value of various derivatives and their reactions.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Zachary L. Magnuson, Qigan Cheng, Weijie Zhang, Yu-Sheng Chen, Lukasz Wojtas, Ayman Nafady, Abdullah M. Al-Enizi, Randy W. Larsen, X. Peter Zhang, Shengqian Ma
Summary: This study successfully synthesized two new metal-metalloporphyrin frameworks (MMPF-12 and MMPF-13) via solvothermal conditions, showing unique structures with either fully or partially metalated ligands, as well as selective adsorption of CO2 and catalytic activity towards CO2 cycloaddition. The enhanced catalytic activity of ligand-metalated MMPF-12 compared to MMPF-13 is likely attributed to the presence of trimer Mn clusters in its structure.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Chemistry, Multidisciplinary
Wan-Chen Cindy Lee, Duo-Sheng Wang, Congzhe Zhang, Jingjing Xie, Bo Li, X. Peter Zhang
Summary: A catalytic radical process for asymmetric cyclopropanation using Co(II)-based metalloradical catalysis has been developed, enabling the stereoselective synthesis of chiral cyclopropyl alpha-amino acid derivatives with high yields, excellent enantioselectivities, and (Z)-diastereoselectivity. Computational and experimental studies support a stepwise radical mechanism for the reaction, showcasing potential applications in the synthesis of dipeptides.
Article
Chemistry, Multidisciplinary
Xavier Riart-Ferrer, Peng Sang, Jingran Tao, Hao Xu, Li-Mei Jin, Hongjian Lu, Xin Cui, Lukasz Wojtas, X. Peter Zhang
Summary: TrocN(3) serves as a potent nitrogen radical precursor for radical olefin aziridination catalyzed by a new Co(II)-based catalytic system, with the cobalt(II) complex of a D-2-symmetric chiral amidoporphyrin proving to be an efficient catalyst. This represents the first example of asymmetric intermolecular olefin aziridination using carbonyl azides as the nitrogen source, allowing for the enantioselective synthesis of various chiral amine derivatives.
Article
Chemistry, Multidisciplinary
Weijie Zhang, Ayman Nafady, Chuan Shan, Lukasz Wojtas, Yu-Sheng Chen, Qigan Cheng, X. Peter Zhang, Shengqian Ma
Summary: This study reported a novel metal-metalloporphyrin framework catalyst utilizing halogen bonding as a donor for catalyzing Diels-Alder reactions, showing high efficiency and uniqueness in facilitating organic transformations. Through experimental and computational studies, the substrate molecules were demonstrated to diffuse through the pores of the framework, establishing a host-guest system via the C-Br...pi interaction, which plays a key role in boosting catalytic efficiency. Furthermore, the unique capability of the metal-metalloporphyrin framework highlights new opportunities in using artificial non-covalent binding pockets as highly tunable and selective catalytic materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Xiaoxu Wang, Jing Ke, Yiling Zhu, Arghya Deb, Yijie Xu, X. Peter Zhang
Summary: A highly efficient catalytic method has been developed for asymmetric radical cyclopropanation of alkenes using Co(II)-based metalloradical catalysis, allowing for broad applicability to various substrates through fine-tuning of the synthesized chiral ligands. This new methodology provides access to valuable chiral heteroaryl cyclopropanes in high yields with excellent diastereoselectivities and enantioselectivities. Computational and experimental studies support a stepwise radical mechanism involving α- and γ-metalloalkyl radicals as key intermediates in the Co(II)-based olefin cyclopropanation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Jing Ke, Wan-Chen Cindy Lee, Xiaoxu Wang, Yong Wang, Xin Wen, X. Peter Zhang
Summary: In this study, it was discovered that alpha-alkynyldiazomethanes generated in situ from the corresponding sulfonyl hydrazones in the presence of a base can be used as effective metalloradicophiles in Co(II)-based metalloradical catalysis for asymmetric cyclopropanation reactions. By using a specific chiral ligand, the Co(II)-based metalloradical system can activate different alpha-alkynyldiazomethanes at room temperature, resulting in highly asymmetric cyclopropanation of a wide range of alkenes with high yields and enantioselectivity. Computational and experimental studies provided evidence for the stepwise radical mechanism involved in the Co(II)-catalyzed olefin cyclopropanation reaction, which is associated with a unique alpha-metalloradical intermediate. The resulting enantioenriched alkynyl cyclopropanes can serve as valuable chiral building blocks for stereoselective organic synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Luiz F. T. Novaes, Yi Wang, Jinjian Liu, Xavier Riart-Ferrer, Wan-Chen Cindy Lee, Niankai Fu, Justin S. K. Ho, X. Peter Zhang, Song Lin
Summary: This work presents manganese porphyrin complexes for the electrocatalytic vicinal diazidation of alkenes with sodium azide. Compared to previous studies using MnBr2 catalysis, this protocol shows improved practicality in terms of lower catalyst loading, enhanced safety measures, and increased reactivity towards unactivated terminal alkenes.
Article
Chemistry, Multidisciplinary
Pan Xu, Jingjing Xie, Duo-Sheng Wang, X. Peter Zhang
Summary: Co(II)-based metalloradical catalysis enables the chemoselective intermolecular amination of allylic C-H bonds and achieves remarkable convergence of regioselectivity, diastereoselectivity, and enantioselectivity. The use of modularly designed D-2-symmetric chiral amidoporphyrins as supporting ligands creates a tunable pocket-like environment. This reaction offers a direct route to synthesize valuable chiral alpha-tertiary amines from an isomeric mixture of alkenes.
Article
Chemistry, Multidisciplinary
Wan-Chen Cindy Lee, Jingyi Wang, Yiling Zhu, X. Peter Zhang
Summary: Asymmetric radical bicyclization processes using metalloradical catalysis have been developed to construct chiral chromanones and chromanes with fused cyclopropanes. Through optimization of the chiral amidoporphyrin ligand platform, a Co(II)-metalloradical system can activate different alkene functionalities under mild conditions for effective radical bicyclization, delivering desired products with high yields and excellent control of stereoselectivities. Computational and experimental studies reveal the stepwise radical mechanisms involved in the Co(II)-catalyzed bicyclization processes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Jingyi Wang, Jingjing Xie, Wan-Chen Cindy Lee, Duo-Sheng Wang, X. Peter Zhang
Summary: Asymmetric radical olefin cyclopropanation using Diazomalonates as metalloradicophiles via Co(II) metalloradical catalysis enables efficient stereoselective construction of chiral 1,1-cyclopropanediesters bearing two contiguous chiral centers, with broad substrate scope and high diastereoselectivity and enantioselectivity. Computational and experimental studies support the underlying stepwise radical mechanism, while the resulting enantioenriched (E)-1,1-cyclopropanediesters serve as versatile building blocks for the stereoselective synthesis of different cyclopropane derivatives. Additionally, the enantioenriched (E)-1,1-cyclopropanediesters can be stereoselectively converted to (Z)-diastereomers.