Article
Chemistry, Physical
Juntao Liu, Jiayan Du, Feng Yu, Lan Gan, Guixia Liu, Zheng Huang
Summary: We designed and synthesized cobalt complexes of L2X-type ligands for olefin hydroboration while considering catalyst stability. The complex with iPr phosphinosubstituents showed broad scope, high functional group tolerance, and high catalytic activity in the hydroboration of terminal olefins with pinacolborane. It demonstrated selectivity for linear hydroboration reactions at elevated temperatures, including with olefins conjugated with arene or carbonyl groups that were difficult to achieve with previous catalysts.
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.
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
Christof Bauer, Felix Mueller, Sercan Keskin, Mirijam Zobel, Rhett Kempe
Summary: This study presents a synthesis protocol for generating nanostructured earth abundant metal catalysts, which are efficient and selective in mediating important chemical reactions. By pyrolysis of an inexpensive metal precursor, an easy to synthesize N/C precursor, and a porous support material, the catalyst material can be obtained in a simple, single synthesis step. The application of this catalyst synthesis method successfully produced a highly active cobalt catalyst for the general and selective hydrogenation of aromatic heterocycles, with implications in organic synthesis and hydrogen storage.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Yiting Gu, Jack R. Norton, Farbod Salahi, Vladislav G. Lisnyak, Zhiyao Zhou, Scott A. Snyder
Summary: Under mild conditions, Cp*Rh(2-(2-pyridyl)phenyl)H catalyzes the selective hydrogenation of the C=C bond in alpha,beta-unsaturated carbonyl compounds, and many isolated double bonds. Mechanistic studies show that no radical intermediates are involved, and the catalyst is homogeneous, providing complementarity to existing protocols for similar hydrogenation processes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Cuiping Yu, Weilong Wu, Min Gao, Yu Liu
Summary: This study reports the synthesis and characterization of modified cellulose-supported Rh catalyst. DAC-BINAP-Rh showed excellent catalytic performance in asymmetric hydrogenation and could be easily recycled. This work provides a novel supported catalyst for the application of cellulose in asymmetric catalysis.
Article
Chemistry, Multidisciplinary
Bingxue Liu, Qiang Liu
Summary: In this study, we report a method for the reductive deoxygenation of ketones using a cobalt/Lewis acid catalyst and H-2 as the reductant. We discovered that the newly developed catalyst exhibits dual hydrogenation activities for both ketones and alkenes under the same reaction conditions. This method shows a broad substrate scope, excellent functional-group compatibility, and potential applicability.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Engineering, Environmental
Edgar S. Duran-Uribe, Antonio Sepulveda-Escribano, Enrique V. Ramos-Fernandez
Summary: Transition metal phosphides have attracted great interest as catalysts for hydrogenation reactions. In this study, cobalt phosphide nanoparticles supported on carbon were synthesized using microwave assistance and applied in the hydrogenation of 1-chloro-4-nitrobenzene. The catalytic activity was found to depend on the reduction temperature, with the phosphorus-rich cobalt phosphide obtained at low temperatures exhibiting the highest activity.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Applied
Hong-Xin Jiang, Dan-Dan Han, Rui-Ping Song, Qin Shi, Xiao-Fan He, Wan-Qing Kou, Qi Zhao, You-Dong Shao, Dao-Juan Cheng
Summary: Here, a chiral boro-phosphate catalyst is presented for an atroposelective asymmetric transfer hydrogenation method, allowing the synthesis of axially chiral styrene-type allyl alcohols. This dynamic kinetic resolution approach offers a simple procedure, mild conditions, and good enantiocontrol (51-95% ee), providing an important alternative for constructing challenging atropisomeric aryl-acyclic alkene scaffolds.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Jianrong Steve Zhou, Siyu Guo, Xiaohu Zhao, Yonggui Robin Chi
Summary: Nickel complexes ligated by strongly donating diphosphines catalyze enantioselective hydrogenation for the preparation of acyclic and cyclic beta-amido esters, with a combination of acetic acid and indium powder providing protons and electrons to form nickel hydrido complexes under umpolung hydrogenation conditions.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Wei Hao, Candice L. Joe, Sloan Ayers, Andrea Daru, Ryan A. Daley, Michal Domanski, Jason S. Chen, Michael A. Schmidt, Donna G. Blackmond
Summary: This study reported a highly efficient and enantioselective asymmetric hydrogenation catalyzed by Ru-DTBM-segphos for a broad range of pyridine-pyrroline trisubstituted alkenes, revealing the reaction mechanism through kinetic, spectroscopic, and computational studies, as well as an intriguing Ru-catalyzed H/D exchange process.
Article
Chemistry, Physical
Wei Hao, Candice L. Joe, Sloan Ayers, Andrea Daru, Ryan A. Daley, Michal Domanski, Jason S. Chen, Michael A. Schmidt, Donna G. Blackmond
Summary: A highly efficient and enantioselective Ru-DTBM-segphos catalyzed asymmetric hydrogenation of pyridine-pyrroline trisubstituted alkenes is reported. Kinetic, spectroscopic, and computational studies suggest that the rate-determining step is the addition of H2, alkene insertion determines the enantioselectivity, and the presence and position of the pyridine nitrogen are critical for enantioselectivity. These studies also reveal a Ru-catalyzed H/D exchange process facilitated by the substrate at room temperature and low pressure, where hydrogenation activity is suppressed. A mechanistic proposal is provided to further define the roles of hydrogen gas, Ru-H species, and protic solvents in this catalytic system.
Article
Chemistry, Multidisciplinary
Ronghua Zhang, Shan Xu, Zhou Luo, Yuanyuan Liu, Junliang Zhang
Summary: Central chirality is an important aspect in the design of chiral ligands and catalysts. This study focuses on the exploration of N-chirality in chiral ligand design, which has been rarely studied before. The authors demonstrate the design, synthesis, and application of a class of P,N-ligands with flexible N-chirality and their derived iridium complexes with fixed N-chiral stereocenters. Computational studies emphasize the importance of N-chirality and the N-H group in the catalytic activity of these complexes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Lauren N. Mendelsohn, Connor S. MacNeil, Lei Tian, Yoonsu Park, Gregory D. Scholes, Paul J. Chirik
Summary: The catalytic hydrogenation activity of a coordinatively saturated cobalt(I) precatalyst is described, showing improved performance under blue light irradiation. Under thermal conditions, a hydrogen atom transfer pathway is enabled by a weak cobalt-hydrogen bond, while under photocatalytic conditions, a coordination-insertion sequence is supported after light-induced dissociation of a carbonyl ligand. This study demonstrates the versatility of catalysis with Earth-abundant metals by switching between open- and closed-shell intermediates based on the energy source.
Article
Chemistry, Physical
Wen-Bin Xie, Zhi Li
Summary: A series of chiral compounds were designed and synthesized for a highly enantioselective intramolecular hydroalkoxylation of nonactivated alkenes, resulting in the formation of 2-methylcoumarans with up to 99% yields and up to 97% enantiomeric excess under mild conditions.
Article
Chemistry, Multidisciplinary
Gabriele Hierlmeier, Paolo Tosatti, Kurt Puentener, Paul J. J. Chirik
Summary: This study reports a new molybdenum ligand for catalyzing the hydrogenation of benzene, which is formed by the coordination of phosphino(imino)pyridine and cyclooctadiene. The experimental results indicate that the ligand can selectively generate cyclohexane catalyst in the presence of benzene, and the formation of the insertion product is a key step.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Editorial Material
Chemistry, Inorganic & Nuclear
Paul J. Chirik
Article
Chemistry, Physical
Paul O. Peterson, Matthew Joannou, Eric M. Simmons, Steven R. Wisniewski, Junho Kim, Paul J. Chirik
Summary: The synthesis and characterization of phenoxy(imine) iron(II) alkyl precatalysts for C(sp2)-C(sp3) Suzuki-Miyaura cross-coupling reaction is reported. This method utilizes mild alkoxide bases and nonpolar solvents to achieve high efficiency C(sp2)-C(sp3) bond formation with various aryl boronic esters and alkyl bromides. The study also highlights the compatibility of the precatalysts with base-sensitive functionality and the role of boronate intermediates in transmetalation.
Article
Chemistry, Multidisciplinary
Marius D. R. Lutz, Hongyu Zhong, Nils Trapp, Bill Morandi
Summary: We reported the synthesis of coordinatively unsaturated cationic rhodium complexes with the sterically encumbered electron-rich NHC ligand IPr*(OMe). The resulting complexes showed unusual coordination geometries and bonding patterns, and exhibited potential as versatile precatalysts for various transformations.
HELVETICA CHIMICA ACTA
(2023)
Article
Chemistry, Organic
Lauren N. Mendelsohn, Connor S. MacNeil, Madison R. Esposito, Tyler P. Pabst, David K. Leahy, Ian W. Davies, Paul J. Chirik
Summary: The cobalt-catalyzed asymmetric hydrogenation of indazole-containing enamides relevant to the synthesis of Zavegepant, a CGRP receptor antagonist, which is approved for the treatment of migraines, is described. Both neutral and cationic bis(phosphine)cobalt complexes were efficient precatalysts, providing excellent yield and enantioselectivities for related substrates, with key reactivity differences observed. The hydrogenation of the indazole-containing enamide was successfully scaled up to 20 g.
Article
Chemistry, Applied
Paul J. Chirik, Keary M. Engle, Eric M. Simmons, Steven R. Wisniewski
Summary: Earth-abundant metal (EAM) catalysis has significant impact on the sustainability and cost improvement in the pharmaceutical industry. It replaces precious metals like palladium and utilizes the reactivity of first-row metals to enable more efficient routes to clinical candidates. This article describes the strategy for building these capabilities within the process group, including the development of a reaction screening platform, scalability demonstration, and increasing mechanism understanding.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2023)
Article
Chemistry, Inorganic & Nuclear
Boran Lee, Tyler P. Pabst, Gabriele Hierlmeier, Paul J. Chirik
Summary: Cobalt complexes with 2,6-diaminopyridinesubstituted PNP pincer ligand were synthesized and studied. The PNP pincer ligand showed higher rigidity and electron-donating properties compared to the iPrPNP ligand. The coordination sphere of the metal was completed by a fourth ligand, resulting in planar, diamagnetic, four-coordinate complexes. Computational studies indicated that the increased rigidity of the pincer ligand led to a higher barrier for C-H oxidative addition. The reduced reactivity of (iPrPNMeNP)CoMe enabled it to be an efficient precatalyst for alkene hydroboration.
Article
Chemistry, Inorganic & Nuclear
Yoonsu Park, Hongyu Zhong, Tyler P. Pabst, Junho Kim, Paul J. Chirik
Summary: The synthesis and characterization of pentamethylcyclopentadienyl iron complexes with redox noninnocent alpha-diimine (MesDI) and alpha-iminopyridine (MesPI) ligands were investigated. Reduction and complexation of the cyclopentadienyl ring were achieved via treatment of (kappa 2-N,N ')FeCl2 (N,N '= MesDI or MesPI) precursors with [C5Me5]Li. The resulting iron compounds were characterized through paramagnetic 1H NMR spectroscopy, magnetic susceptibility measurements, zero-field 57Fe Mössbauer spectroscopy, low-temperature electron paramagnetic resonance (EPR) spectroscopy, and cyclic voltammetry. The spectroscopic, structural, and density functional theory (DFT) computational data confirmed the presence of low-spin iron(III) compounds (SFe = 1/2) with pi-acidic, formally doubly reduced chelating ligands.
Article
Chemistry, Multidisciplinary
L. Reginald Mills, Francesca Di Mare, David Gygi, Heejun Lee, Eric M. Simmons, Junho Kim, Steven R. Wisniewski, Paul J. Chirik
Summary: The relative rates of the cobalt-catalyzed C(sp(2))-C(sp(3)) Suzuki-Miyaura cross-coupling were evaluated, and it was found that smaller N-alkyl substituents on the phenoxyimine ligand accelerated the reaction. This inspired the design of optimal cobalt catalysts with phenoxyoxazoline and phenoxythiazoline ligands. The catalyst lifetime was improved by adding excess KOMe•B(O-iPr)3, which attenuated alkoxide basicity and prevented demetallation of the ligand.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Gabriele Hierlmeier, Paolo Tosatti, Kurt Puentener, Paul J. Chirik
Summary: This study describes the synthesis of phosphino(oxazoline)pyridine-supported molybdenum(0) cycloocta-1,5-diene complexes and their reactions with dihydrogen and arenes. The study found that the site selectivity of arene insertion reactions depended on the size of the substituent, and electron-rich arenes had faster insertion rates. Additionally, through mechanistic studies, the synthesis of enantioenriched cyclohexa-1,3-diene was achieved.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
L. Reginald Mills, David Gygi, Eric M. Simmons, Steven R. Wisniewski, Junho Kim, Paul J. Chirik
Summary: The mechanism of phenoxyimine (FI)-cobalt-catalyzed C(sp(2))-C(sp(3)) Suzuki-Miyaura cross-coupling was studied using kinetic measurements and catalytic and stoichiometric experiments. Dimeric (FI) cobalt(II) bromide complexes were isolated and characterized, and one complex was used as a single-component precatalyst for the cross-coupling reaction. The involvement of boronate intermediates in transmetalation was confirmed by Hammett studies of aryl boronic esters. A cobalt(II)/cobalt(III) catalytic cycle was proposed that proceeds through a boronate-type mechanism.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Coralie Duchemin, Amelia I. Liu, Junho Kim, Paul J. Chirik
Summary: This study describes the synthesis, characterization, and reactivity of a series of quinoline pyridine(imine) iron dichloride complexes. The complexes were found to be effective catalysts for the hydrovinylation reaction of butadiene with ethylene, showing high selectivity for the hexa-1,4-diene isomer.
Article
Chemistry, Multidisciplinary
Coralie Duchemin, Junho Kim, Paul J. J. Chirik
Summary: A series of C-S-symmetric (aryl,alkyl)-substituted pyridine(dimine) iron methyl ((Cy)ARPDI)FeCH3 complexes have been synthesized and used as precatalysts for [2+2] cycloaddition. The chemoselectivity of the reaction is affected by the stability and resting state of the catalyst, leading to the formation of vinylcyclobutane and (Z)-hexa-1,4-diene.
Article
Chemistry, Organic
Song-Zhou Cai, Rongrong Yu, Can Li, Hongyu Zhong, Xichang Dong, Bill Morandi, Juntao Ye, Xianjie Fang
Summary: Hydrothiocarbonylation of olefins using carbon monoxide and thiols is a powerful method to synthesize thioesters. However, transition-metal-catalyzed asymmetric thiocarbonylation, particularly with earth abundant metals, is rarely reported. In this study, a nickel-catalyzed enantioselective hydrothiocarbonylation of cyclopropenes was developed for the synthesis of functionalized thioesters with high stereoselectivity.
Article
Chemistry, Inorganic & Nuclear
Junho Kim, Yoonsu Park, Paul J. Chirik
Summary: Piano-stool iridium hydride complexes with phenylpyridine ligands are effective in promoting element-hydrogen bond formation using H-2 as a H-atom source. Blue light irradiation enhances the catalyst turnover for iridium-catalyzed hydrogenation of aryloxyl radicals. The reaction involves proton-coupled electron transfer and formation of an iridium compound. Blue light irradiation with H-2 releases a free heterocycle and regenerates the iridium hydride precatalyst, leading to increased turnover.
INORGANIC CHEMISTRY
(2023)
