Article
Chemistry, Organic
Yingjie Gong, Jingxi He, Xiaoting Wen, Hui Xi, Zhihong Wei, Weiping Liu
Summary: A convenient manganese-catalyzed transfer hydrogenation method using alcohols as hydrogen sources for N-heteroarenes was presented. The use of a specific manganese pincer complex allowed for good to excellent isolated yields, with even biomass-derived ethanol being a viable option for the process. Detailed DFT calculations supported an outer sphere hydrogenation mechanism with hydride transfer as the rate-determining step.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Dawei Gong, Degong Kong, Na Xu, Yuhui Hua, Bo Liu, Zhanlin Xu
Summary: A new method for the synthesis of hydrazoarenes is developed by using ethanol as a hydrogen source and a bidentate Ru(II)-NC complex as the catalyst. The presence of a weak base is crucial for efficient semihydrogenation, which prevents hydrazoarene dehydrogenation under strongly basic conditions. Control experiments and density functional theory calculations confirm the mechanism as Meerwein-Ponndorf-Verley mechanism, with ethyl acetate as the only byproduct. This study offers a new and simple approach for the synthesis of hydrazoarenes.
Article
Chemistry, Physical
Rahul Ghosh, Rakesh R. Behera, Surajit Panda, Sandeep K. Behera, Narayan Ch Jana, Bidraha Bagh
Summary: The synthesis of a new iron(II) complex and its application in the catalytic reduction of lignocellulosic biomass into fine chemicals was investigated. The results showed that the synthesized complex exhibited promising catalytic performance and could effectively reduce various target compounds.
Article
Chemistry, Inorganic & Nuclear
Richard J. Citta, Brandon L. Koteles, Brenda Delgado-Perez, Benny C. Chan, Steven E. Kalman
Summary: Two half-sandwich ruthenium(II) complexes of an imidazole-2-carboxamido ligand were synthesized and characterized, serving as precatalysts for base-free transfer hydrogenation under aerobic conditions. A substrate scope study with ketones and aldehydes was conducted, along with a preliminary investigation of the catalytic mechanism. These complexes are rare examples of transfer hydrogenation catalysts that do not require an inert atmosphere and an exogenous base.
Article
Chemistry, Physical
Yutichai Mueanngern, Cheng-Han Li, Meiling Spelic, Joshua Graham, Nathan Pimental, Yehia Khalifa, Joerg R. Jinschek, L. Robert Baker
Summary: Ni based catalysts with controlled sub-monolayer deposition of CeO2 nanocubes show significantly enhanced H-2 production for ethanol steam reforming. The active catalysts exhibit significant C deposition on the surface without deactivation, forming a Ni@CFIL active phase. Mesoscale morphology of CeO2 nanocubes plays a key role in templating the formation of the Ni@CFIL catalyst for stable H-2 production.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Thomas G. Linford-Wood, Nathan T. Coles, Ruth L. Webster
Summary: This study reports the reduction of carbon-carbon double bonds using a three-coordinate iron(ii) beta-diketiminate pre-catalyst, employing poly(methylhydrosiloxane) as the hydride donor and a bio-alcohol as the proton source. The results show that allyl arene substrates, styrenes, and aliphatic substrates can all undergo reduction at room temperature using n-butanol and ethanol. Additionally, by changing the deuterium source to d-aniline, high regioselectivity for mono-deuteration of the terminal position of the double bond can be achieved.
Article
Chemistry, Physical
Joshua S. Sapsford, Daniel Csokas, Roland C. Turnell-Ritson, Liam A. Parkin, Andrew D. Crawford, Imre Papai, Andrew E. Ashley
Summary: The newly synthesized compound iPr(3)SnNTf(2) exhibits stronger Lewis acid properties compared to previously studied compounds, enabling faster hydrogen activation and catalytic hydrolysis of ester bonds. The reaction outcome is influenced by the steric and electronic properties of the substrate, with computational studies revealing differences in the reaction mechanisms between different ester substrates.
Article
Chemistry, Physical
Phil Preikschas, Milivoj Plodinec, Julia Bauer, Ralph Kraehnert, Raoul Naumann d'Alnoncourt, Robert Schloegl, Matthias Driess, Frank Rosowski
Summary: Catalysts tested for reactions exhibit dynamic structural changes that significantly impact product selectivity and reaction rates, especially in the conversion of synthesis gas to ethanol. Understanding and controlling the catalyst morphology is crucial for optimizing catalytic processes.
Article
Chemistry, Organic
Jiufeng Wu, Claire M. Young, Andrew D. Smith
Summary: A new protocol has been developed for the isothiourea-catalysed transfer hydrogenation of alpha,beta-unsaturated para-nitrophenyl esters using Hantzsch ester. Good to excellent yields were observed, especially with alpha,beta-unsaturated aryl esters bearing electron-withdrawing beta-substituents. The aryl ester products can be isolated directly in moderate to excellent yields or converted to methyl esters or benzyl amides after in situ reaction with the appropriate nucleophile. Preliminary experiments showed modest enantioinduction when a chiral isothiourea catalyst was used.
Article
Chemistry, Inorganic & Nuclear
Zhenwei Ni, Rosa Padilla, Rajib Pramanick, Mike S. B. Jorgensen, Martin Nielsen
Summary: A base-free, acceptorless dehydrogenative coupling of ethanol to ethyl acetate is achieved using a pincer complex ((PNP)-P-Ph)RuH(BH4)(CO) (0.25 mol%) and m-xylene as the co-solvent. The catalysis shows excellent conversion and yield of >99% after 24 h at 120 degrees C. The scaled-up reaction is also effective under similar conditions.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Organic
Xiaoting Wen, Yingjie Gong, Shuodong Niu, Tianjun Luo, Hui Xi, Weiping Liu
Summary: A convenient PNP pincer manganese catalyzed transfer hydrogenation of bromides to corresponding debrominated aryl compounds using ethanol as the hydrogen source is reported. The application of biomass-derived ethanol highlights the sustainability of the methodology. The use of 6-phenyl substituted triazine-based (PNPipr)-N-ipr-P-5 manganese pincer catalyst allows for the debromination of various aryl bromides with good yields, including those derived from natural products and bioactive compounds.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Yueyue Li, Ruonan Wang, Bowen Huang, Liangliang Zhang, Xuran Ma, Shikun Zhang, Zhiguo Zhu, Hongying Lu, Kaixuan Yang
Summary: This study reported an efficient catalyst for the conversion of HMF to high-value-added chemical DMF. The catalyst showed excellent stability and reusability, and achieved selective conversion of HMF by modulating the electronic structure of nickel. Furthermore, the synergy between acid-base sites and indium played a crucial role in the catalytic process.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Inorganic & Nuclear
Zheng Wang, Yahuan Liu, Mingyang Han, Ning Ma, Quanming Lyu, Qingbin Liu, Wen-Hua Sun
Summary: Molybdenum complexes with various structural features were developed and showed high activity in the transfer hydrogenation reaction. The products can be easily purified by removing the byproduct.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Physical
Abhishek Kumar, Ritu Bhardwaj, Sanajit Kumar Mandal, Joyanta Choudhury
Summary: Progress has been made in the application of transfer hydrogenation strategy for CO2 reduction in the past decade. The use of biomass-derived alcohols as hydride donors shows promise in replacing traditional hydrogenation process. However, finding efficient and stable homogeneous catalysts under harsh reaction conditions remains a challenge.
Article
Chemistry, Applied
Xiao-Gen Li, Fu Li, Yue Xu, Li-Jun Xiao, Jian-Hua Xie, Qi-Lin Zhou
Summary: The hydrogenation of esters catalyzed by a manganese complex of phosphine-aminopyridine ligand was developed. A variety of esters, including biomass-derived esters and lactones, can be efficiently hydrogenated to primary alcohols with yields of 63-98%. The manganese catalyst showed high activity for the hydrogenation of methyl benzoate, with turnover numbers (TON) as high as 45,000. Investigation of catalyst intermediates revealed that the amido manganese complex is the active species for the reaction.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Ronald A. Farrar-Tobar, Stefan Weber, Zita Csendes, Antonio Ammaturo, Sarah Fleissner, Helmuth Hoffmann, Luis F. Veiros, Karl Kirchner
Summary: This study describes the selective semihydrogenation of alkynes using a Mn(I) alkyl catalyst, leading to good to excellent yields of E-alkenes. Mechanistic investigations reveal that the initially formed Z-isomer undergoes fast isomerization to the thermodynamically more stable E-isomer.
Article
Chemistry, Multidisciplinary
Johannes G. de Vries
Summary: This article reviews various processes for converting lignocellulose or sugars into useful chemicals. Catalytic pyrolysis of lignocellulose produces hydrocarbon mixtures rich in alkenes or aromatics. These processes can also be applied to plastic waste or mixtures of biomass and plastic waste. New applications of furfural are emerging, and the production of furfural derivatives, such as 2-methyltetrahydrofuran, is increasing. The production of levulinic acid and its derivatives is about to be scaled up. Additionally, there are several processes in development for the production of glycols from glucose or bioethanol, and a plant for converting bioethanol into butadiene is currently under construction in Poland.
CURRENT OPINION IN GREEN AND SUSTAINABLE CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Soumyadeep Chakrabortty, Katharina Konieczny, Felix J. de Zwart, Eduard. O. Bobylev, Eszter Barath, Sergey Tin, Bernd H. Mueller, Joost N. H. Reek, Bas de Bruin, Johannes G. de Vries
Summary: Researchers achieved enantioselective hydrogenation of cyclic enamides using an earth-abundant cobalt-bisphosphine catalyst. The catalytic system, CoCl2/(S,S)-Ph-BPE, reduced trisubstituted carbocyclic enamides to saturated amides with high activity and excellent enantioselectivity (up to 99%). The methodology can be extended to the synthesis of chiral amines by base hydrolysis of the hydrogenation products. Preliminary mechanistic investigations suggested a sigma-bond-metathesis pathway for the hydrogenation of the carbon-carbon double bond, involving a high spin cobalt (II) species.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Soumyadeep Chakrabortty, Shasha Zheng, Fabian Kallmeier, Eszter Barath, Sergey Tin, Johannes G. de Vries
Summary: A readily available chiral Ru/bisphosphine catalyst was used to achieve the direct asymmetric reductive amination of bio-based levulinic acid (LA) to produce enantioenriched 5-methylpyrrolidinone with excellent enantioselectivity (up to 96% ee) and high isolated yield (up to 89%). Methyl levulinate (ML), a byproduct from the industrial production of 2,5-furandicarboxylic acid (FDCA), can be used as a substitute for LA with similar reactivity and selectivity. Mass spectrometry and isotope labelling studies suggest that the chiral lactam is formed through imine-enamine tautomerization/cyclization followed by asymmetric hydrogenation of the cyclic enamide.
Article
Biochemistry & Molecular Biology
Kyzgaldak Ramazanova, Soumyadeep Chakrabortty, Fabian Kallmeier, Nadja Kretzschmar, Sergey Tin, Peter Loennecke, Johannes G. de Vries, Evamarie Hey-Hawkins
Summary: Sulfur-protected enantiopure P-chiral 1-phosphanorbornane silyl ethers 5a,b were obtained in high yields via reaction with tert-butyldimethylsilyl chloride (TBDMSCl) and triphenylsilyl chloride (TPSCl), and were subsequently purified and characterized. The bulky monodentate enantiopure phosphorus(III) 1-phosphanorbornane silyl ethers 6a,b were obtained by desulfurization with excess Raney nickel, and showed better activity and selectivity as ligands in iridium-catalyzed asymmetric hydrogenation.
Article
Green & Sustainable Science & Technology
Shasha Zheng, Zhihong Wei, Bartosz Wozniak, Fabian Kallmeier, Eszter Barath, Haijun Jiao, Sergey Tin, Johannes G. de Vries
Summary: This article introduces a strategy for synthesizing benzenoid aromatics from bio-based feedstock, which shows the potential to replace fossil-based resources in aromatics production.
NATURE SUSTAINABILITY
(2023)
Article
Chemistry, Physical
Shahbaz Ahmad, Ellis Crawford, Muhammad Bilal, Johannes G. de Vries, Michael Buhl
Summary: The detailed mechanism for ruthenium-catalysed selective reduction of cardanol derivatives by transfer hydrogenation has been fully characterised at the B3PW91-D3/ECP2/PCM//B3PW91/ECP1 level of density functional theory. The catalytic cycle involves the hydrogenation of the triene cardanol giving the diene product via a highly stable eta(3)-allylic intermediate. The further reduction to the cardanol monoene product required elevated temperatures and had a high overall barrier, explaining the observed selectivity towards the monoene product.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Kyzgaldak Ramazanova, Soumyadeep Chakrabortty, Bernd H. Mueller, Peter Loennecke, Johannes G. de Vries, Evamarie Hey-Hawkins
Summary: A convenient synthesis method for enantiopure mixed donor phosphine-phosphite ligands has been developed, incorporating P-stereogenic phosphanorbornane and axially chiral bisnaphthols into one ligand structure. These ligands exhibited excellent selectivity and moderate enantioselectivity in various catalyzed reactions.
Article
Chemistry, Multidisciplinary
Andrea Dell'Acqua, Claas Schuenemann, Eszter Barath, Sergey Tin, Johannes G. de Vries
Summary: In this study, the hydroformylation and methoxycarbonylation of MVG were investigated to produce novel bifunctional monomers. Polyesters with high renewable-atom content were successfully prepared and characterized.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Xin Liu, Yujing Zuo, Fabian Kallmeier, Esteban Mejia, Sergey Tin, Johannes G. de Vries, Eszter Barath
Summary: Silicon-modified polyureas were successfully depolymerized using hydrogenation with Ru and Mn catalysts, resulting in high yields of aliphatic diamine and silicon-containing diamine.
CHEMICAL COMMUNICATIONS
(2022)
