Review
Chemistry, Applied
Seoung-Mi Choi, Ju Hyun Kim
Summary: This review summarizes the progress made in the synthesis of 2H-pyrroles since 2000, including methods such as dearomatization of 1H-pyrrole, oxidation of pyrrolines or pyrrolidines, ring construction via catalytic cycloaddition, and rearrangement of 3H-pyrroles.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Vibha V. Kanale, Christopher Uyeda
Summary: Cobalt catalysts facilitate highly enantioselective ring-opening reactions of 2,5-dihydrofurans using vinylidenes. The resulting products are acyclic organozinc compounds, capable of further functionalization with an electrophile. The proposed mechanism involves the formation of a cobalt vinylidene species that adds to the alkene via a [2+2]-cycloaddition pathway, followed by ring-opening through outer-sphere & beta;-O elimination assisted by a ZnX2 Lewis acid. DFT models explain the observed stereochemical outcome by suppressing competing inner-sphere syn & beta;-H and & beta;-O elimination pathways due to the geometric constraints of the metallacycle intermediate. Cobalt catalysts also promote enantioselective ring-opening reactions of unstrained heterocycles via reductive addition of 1,1-dichloroalkenes. The resulting products are acyclic homoallylic alcohols with a vinylzinc motif, which can be further modified with an electrophile. Mechanistic studies suggest that the ring-opening occurs through outer-sphere & beta;-O elimination facilitated by a Zn(II) Lewis acid.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Takeshi Yasui, Rine Tatsumi, Yoshihiko Yamamoto
Summary: In this study, a dual cobalt and photoredox catalysis was utilized for the [2+2+2] cycloaddition of enediynes to produce tricyclic cyclohexadienes with a quaternary bridgehead carbon. The use of a chiral ligand, (S)-Segphos, enabled highly enantioselective reactions, leading to highly enantio-enriched cyclohexadienes.
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, Physical
Connor S. MacNeil, Hongyu Zhong, Tyler P. Pabst, Michael Shevlin, Paul J. Chirik
Summary: The cobalt-catalyzed asymmetric hydrogenation of dehydro-sitagliptin was studied and applied to the synthesis of sitagliptin. The discovery of catalysts was accelerated by the synthesis of cationic bis(phosphine) cobalt eta 6-arene complexes. The optimal catalyst showed high yield and enantioselectivity, and maintained excellent activity and selectivity after standing in air for 2 weeks.
Review
Chemistry, Multidisciplinary
Stefan Simic, Erna Zukic, Luca Schmermund, Kurt Faber, Christoph K. Winkler, Wolfgang Kroutil
Summary: Biocatalysis, using enzymes for organic synthesis, is a powerful tool for the synthesis of active pharmaceutical ingredients (APIs). Developments in molecular biology methods have led to the rapid development of process-stable enzymes through directed evolution. Enzymes are widely employed in the synthesis of small molecule APIs, enabling more efficient and sustainable routes.
Article
Chemistry, Applied
Maxime Denis, Samuel Blais, Sylvain Canesi
Summary: A stereoselective synthesis of isolycoricidine, a natural product belonging to the Amaryllidaceae alkaloids family, was achieved. The study also conducted a synthetic investigation on the main core of lycoricidine, resulting in the formation of analogues and a diastereomer of dihydrolycoricidine. The research utilized various strategies including oxidative phenol dearomatization, stereoselective Heck process, selective dihydroxylation, stereoselective reductions, and oxidative retro-Michael procedure as an amine-deprotecting group strategy. In addition, the study highlighted the usefulness of hypervalent iodines in total synthesis of natural products.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Aibo Li, Xinjian Song, Qiao Ren, Peiwang Bao, Xinyu Long, Fuli Huang, Lvjiang Yuan, Jianrong Steve Zhou, Xurong Qin
Summary: A cobalt-catalyzed deuteration of amidoacrylates using deuterated methanol resulted in the synthesis of highly enantioselective α,β-dideuterio-α-amino esters with almost complete deuteration (99%). This new protocol was successfully employed for the preparation of dideuterio-α-amino acid fragments in certain drugs, and also applied in the concise synthesis of dideuterio L-DOPA.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Wenke Dong, Zhiyang Ye, Wanxiang Zhao
Summary: Catalytic asymmetric hydroboration of ketone-derived silyl enol ethers using cobalt catalyst has been reported, providing a convenient approach to access valuable enantiopure beta-hydroxy boronic esters. This method features mild reaction conditions, a broad substrate scope, and excellent enantioselectivities, making it potential to streamline the synthesis of complex molecules.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Zeng-Hua Wu, An-Qi Cheng, Meng Yuan, Ya-Xuan Zhao, Huai-Lan Yang, Li-Hua Wei, Huai-Yu Wang, Tao Wang, Zunting Zhang, Wei-Liang Duan
Summary: Utilizing the pyridinyl moiety as the coordinating group in cobalt-catalysed asymmetric nucleophilic addition/alkylation of secondary phosphine oxides can lead to the efficient synthesis of tertiary phosphine oxides with high yields and high enantiomeric excess, along with broad functional-group tolerance. Mechanistic studies reveal that (R)-secondary phosphine oxides preferentially interact with the cobalt catalysts to produce P-stereogenic compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Yanhua Hu, Yashi Zou, Huiwen Yang, Haotian Ji, Yue Jin, Zhenfeng Zhang, Yangang Liu, Wanbin Zhang
Summary: Asymmetric sequential hydrogenations of conjugated enynes have been developed using a Ph-BPE-Co-I catalyst for the precise synthesis of chiral Z-allylamides with high activity and excellent enantioselectivity. The difference in catalytic activity between cobalt complexes of Ph-BPE and QuinoxP* was explained by the process decomposition of rate-determining step in the second hydrogenation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Boon Beng Tan, Ming Hu, Shaozhong Ge
Summary: A ligand-controlled cobalt-catalyzed ring-opening dihydroboration method is developed to access versatile skipped diboronates. Various arylidenecyclopropanes reacted with pinacolborane to yield 1,3- or 1,4-diboronate products with high regioselectivity. The resulting diboronates can undergo various transformations, enabling selective installation of different functional groups on alkyl chains.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Hua Chen, Ju Peng, Qinjiao Pang, Huimin Du, Liying Huang, Lu Gao, Yu Lan, Cheng Yang, Zhenlei Song
Summary: Silaspiranes with chiral spiro-silicon center have unique properties. This study reports a novel method to synthesize axially chiral spirosilabicyclohexenes with a 6/6-silaspirane framework through the reaction of alkynes with spirosilabicyclobutanes. The origin of high enantioselectivity is revealed by DFT calculations. Preliminary studies show that one of the spirosilabicyclohexene analogs exhibits fluorescence emission, Cotton effects, and CPL activity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Dipshi Singh, T. V. RajanBabu
Summary: We report two distinctly different, catalyst-dependent, modes of regio- and enantioselective cycloaddition reactions between alkynes and 1,3-dienes providing rapid access to highly functionalized 1,4-cyclohexadienes or cyclobutenes from the same precursors. Complexes of an earth abundant metal, cobalt, with several commercially available chiral bisphosphine ligands with narrow bite angles catalyze [4+2]-cycloadditions with excellent chemo-, regio- and enantioselectivities. In contrast, complex of a finely tuned phosphino-oxazoline ligand promotes unique [2+2]-cycloaddition between the alkyne and the terminal double bond of the diene giving a highly functionalized cyclobutene with excellent regio- and enantioselectivities.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Kristers Ozols, Shunsuke Onodera, Lukasz Wozniak, Nicolai Cramer
Summary: The study presents a method for highly enantioselective intermolecular carboaminations of alkenes through C-H activation catalyzed by high-valent cyclopentadienyl cobalt complexes. This method converts widely available acrylates and bicyclic olefins into enantioenriched isotyrosine derivatives and amino-substituted bicyclic scaffolds under very mild conditions. The reactivity outlined in this research is unique to the (CpCoIII)-Co-x complexes and complements the reactivity of 4d- and 5d- precious-metal catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
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
Jingjing Xie, Pan Xu, Yiling Zhu, Jingyi Wang, Wan-Chen Cindy Lee, X. Peter Zhang
Summary: By optimizing the Co(II)-based metalloradical catalyst with a chiral ligand, a new catalytic radical process has been developed for asymmetric 1,4-C-H alkylation of diazoketones, leading to the construction of chiral cyclobutanone structures with high stereoselectivity. This process offers a mild and efficient method for the synthesis of enantioenriched cyclobutanones with potential applications in stereoselective organic synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Mojtaba Hajiloo Shayegan, Zhong-Yuan Li, Xin Cui
Summary: This study achieved ligand-controlled regiodivergence for the catalytic semireduction of allenamides with excellent chemo- and stereocontrol.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
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, Organic
Hetti Handi Chaminda Lakmal, Jacob Istre, Xiaolin Qian, Hui Zhou, Henry U. Valle, Xue Xu, Xin Cui
Summary: A chemo-switchable catalytic [2+2+2] cydoaddition method using alkenes with formaldimines has been reported. The synthesis of hexahydropyrimidine and 2,4-diarylpiperidine derivatives were achieved using two different pathways, one involving the 'imine-alkene-imine' addition mechanism and the other involving the retro-[2+2] reaction, respectively. The reactions were catalyzed by environmentally friendly catalysts InCl3 and FeBr2.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Multidisciplinary
Lisa Smith, D. M. Nirosh Udayanga, Xiaolin Qian, Lauren Adams, Sarah Sims, Charles Nettles, Xue Xu, Xin Cui, Deb Mlsna
Summary: This study developed and implemented an iron-based tandem catalysis experiment in an organic chemistry course at Mississippi State University, which successfully achieved the learning objectives of enhancing students' understanding of catalytic cycles and reaction mechanisms through tracking reactions using TLC and (1)H NMR.
JOURNAL OF CHEMICAL EDUCATION
(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.
