Article
Chemistry, Multidisciplinary
Akira Saito, Shinya Adachi, Naoya Kumagai, Masakatsu Shibasaki
Summary: The strategic use of a sterically demanding Ni-II pincer carbene complex has enabled high enantioselectivity in the direct catalytic asymmetric addition of acetonitrile to aldehydes, resulting in highly enantioenriched beta-hydroxynitriles. This highly atom-economical process offers a promising pathway for utilizing inexpensive acetonitrile as a C2 building block in practical synthetic toolbox for asymmetric catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Mingxin Liu, Nguyen Le, Christopher Uyeda
Summary: Nickel catalysts promote nucleophilic cyclopropanation reactions using CH2Cl2 as a methylene source and Mn as a stoichiometric reductant. The substrate scope includes a broad range of alkenes bearing electron-withdrawing substituents, and enantioselective cyclopropanations have been developed using chiral PyBox ligands. Mechanistic studies suggest the intermediacy of a (PyBox)Ni=CH2 species and DFT models provide a rationale for the nucleophilic character of the nickel carbene and the sense of enantioinduction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Francesco Calogero, Giandomenico Magagnano, Simone Potenti, Andrea Gualandi, Andrea Fermi, Paola Ceroni, Pier Giorgio Cozzi
Summary: A regioselective vinylation reaction of aromatic and aliphatic aldehydes, promoted by the merging of photoredox and nickel catalysis, has been reported. Through comprehensive investigation of reaction conditions, a valid and reproducible protocol based on nickel-mediated reductive coupling under visible light irradiation has been disclosed. The use of 3CzClIPN as the photocatalyst and Hantzsch's ester as the organic reductant replaces the commonly used reducing agents, making this method a worthy alternative. The mild reaction conditions allow access to a wide range of substituents on both the aldehyde and the alkyne. Furthermore, careful photophysical investigations have shed light on the reaction mechanism.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Francesco Calogero, Simone Potenti, Elena Bassan, Andrea Fermi, Andrea Gualandi, Jacopo Monaldi, Busra Dereli, Bholanath Maity, Luigi Cavallo, Paola Ceroni, Pier Giorgio Cozzi
Summary: In this study, a highly enantioselective photoredox allylation of aldehydes was developed using commercially available allyl acetate and chiral nickel complexes as the catalyst. The reaction proceeded under visible-light irradiation at low temperature, providing good to excellent yields and high enantioselectivity. This methodology shows great potential for practical applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Ren-Xiao Liang, Heng-Wei Tang, Jia-Liang Liu, Jian-Feng Xu, Ling-Jia Chen, Yi-Xia Jia
Summary: A highly enantioselective cobalt-catalyzed desymmetrizing reductive cyclization of alkynyl cyclodiketones has been developed. This reaction utilizes HBpin as a reducing agent and ferrocene-based PHOX as a chiral ligand to achieve moderate to excellent yields of polycyclic tertiary allylic alcohols with excellent enantioselectivities (up to 99%). The reaction demonstrates broad substrate scope, high functional group compatibility, and a proposed CoH-catalyzed pathway.
Article
Chemistry, Multidisciplinary
Cristian Cavedon, Sebastian Gisbertz, Susanne Reischauer, Sarah Vogl, Eric Sperlich, John H. Burke, Rachel F. Wallick, Stefanie Schrottke, Wei-Hsin Hsu, Lucia Anghileri, Yannik Pfeifer, Noah Richter, Christian Teutloff, Henrike Mueller-Werkmeister, Dario Cambie, Peter H. Seeberger, Josh Vura-Weis, Renske M. van der Veen, Arne Thomas, Bartholomaus Pieber
Summary: We demonstrate visible-light-mediated carbon-heteroatom cross-coupling reactions using a photoactive Ni(II) precatalyst. The activation of this precatalyst involves an initial intraligand charge transfer event triggered by visible light irradiation. Additionally, a porous, recyclable organic polymer for heterogeneous nickel catalysis of cross-coupling reactions is obtained through ligand polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Mateusz Janeta, Julius X. Heidlas, Olafs Daugulis, Maurice Brookhart
Summary: The reactivity of Ni-II and Pd-II olefin polymerization catalysts can be enhanced by introducing electron-withdrawing substituents on the supporting ligands, as demonstrated in this paper. Compared to the trifluoromethyl group, the trippy substituent shows stronger electron-withdrawing ability, leading to better performance in catalytic turnover frequency and polymer molecular weight.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Jinguo Long, Shaomiao Xia, Ting Wang, Gui-Juan Cheng, Xianjie Fang
Summary: A regiodivergent cyanation of allylic alcohols under nickel catalysis was reported in this study, leading to the successful synthesis of challenging branched products. Dinitriles can also be obtained in good yields with high selectivity through subsequent hydrocyanation, which can be further functionalized into various compounds. Density functional theory (DFT) calculations provided insights into the role of ligands in tuning regioselectivity and reactivity.
Article
Chemistry, Multidisciplinary
Ziqi Zhu, Jieshuai Xiao, Mingjie Li, Zhuangzhi Shi
Summary: This study reports for the first time that chiral nickel complexes can catalyze the intermolecular enantioselective addition of aryl iodides across aldehydes, providing diverse optically active secondary alcohols. The method has a broad substrate scope and mild reaction conditions, avoiding the traditional pre-generation of organometallic reagents.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Feixiang Sun, Jiamin Huang, Zhihong Wei, Conghui Tang, Weiping Liu
Summary: A homogeneous manganese-catalyzed cross-coupling reaction of secondary alcohols was developed for the synthesis of gamma-disubstituted alcohols and beta-disubstituted ketones. The protocol, using Mn-MACHO(Ph) as the catalyst, exhibited a wide substrate scope and good functional group tolerance, resulting in diverse valuable disubstituted alcohols and ketones in moderate to good yields. The selective formation of alcohol products was found to be influenced by reaction temperature, with alcohols favored over ketones at lower temperatures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jun Tang, Jingxi He, Sheng-Yin Zhao, Weiping Liu
Summary: Here, we report a manganese-catalyzed three-component coupling reaction for the synthesis of beta,beta-methylated/alkylated secondary alcohols. Our method efficiently constructs assembled alcohols with high chemoselectivity in moderate to good yields using a series of 1-arylethanol, benzyl alcohol derivatives, and methanol. Mechanistic studies suggest that the reaction proceeds via methylation of a benzylated secondary alcohol intermediate to generate the final product.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Daniel Timelthaler, Christoph Topf
Summary: This study presents a simple method for the transfer hydrogenation of aromatic aldehydes in i-PrOH using the cost-effective and easy-to-handle [Cr(CO)(6)] as a catalyst. The reactions can be carried out in normal atmosphere without the need for special equipment, and various functional groups are tolerated. Furthermore, the addition of TMAO can further promote the catalytic transformations. This method is also suitable for processing thermo-labile substrates.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Zhikun Zhang, Xile Hu
Summary: A catalytic deracemization method for secondary benzylic alcohols has been developed, utilizing sequential photochemical dehydrogenation followed by enantioselective thermal hydrogenation. The combination of a heterogeneous dehydrogenation photocatalyst and a chiral molecular hydrogenation catalyst enables the conversion of racemic aryl alkyl alcohols into their enantiomerically enriched forms.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Ryota Osuga, Peixuan Fang, Haruka Nishiyama, Koji Takizawa, Noritoshi Yagihashi, Toshiyuki Yokoi, Junko N. Kondo
Summary: Highly active and long-lived Hf-containing SBA-15 catalysts were successfully synthesized using a sol-gel method for the first time, showing higher specific surface area, mesopore volume, and Hf dispersion compared to conventional Hf-supported catalysts, leading to a higher 1,3-butadiene yield.
MICROPOROUS AND MESOPOROUS MATERIALS
(2022)
Article
Chemistry, Organic
Ni Xiong, Yuanqi Dong, Bin Xu, Yang Li, Rong Zeng
Summary: This study describes a mild protocol for amide formation using nitroarenes as nitrogen sources and an inexpensive iron complex as a catalyst. The method utilizes pH-neutral conditions and avoids the use of strong oxidants or reductants, allowing for tolerance of a wide range of aldehydes and nitroarenes with various functional groups.
Article
Polymer Science
Harshad R. Patil, Sangeetha Karthikeyan, Vikas Kote, Pratyay Sengupta, Pratyagra Samanta, Pooja Kadam, Natarajan Venkateswaran, Virendra Kumar Gupta
Summary: In this study, the molecular weight distribution curves of different polyolefins were deconvoluted to reveal the distribution and characteristics of active sites in different catalysts. The results showed that the JDE method provided a highly accurate fit for the molecular weight distribution of the polymers. This research is of great importance for understanding the role of catalyst active sites and their impact on polymer properties.
Article
Chemistry, Multidisciplinary
Ganesan Sivakumar, Murugan Subaramanian, Ekambaram Balaraman
Summary: The development of sustainable chemical production requires new catalysts and technologies. Researchers have found that a single Mn(I)-PNP catalysis enables the tandem C-C and C-N bond formation through double dehydrogenative coupling of amino alcohols with primary alcohols, resulting in a wide range of N-heterocyclic compounds. This reaction proceeds under solventless conditions, yielding excellent results with hydrogen and water as the only byproducts.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Polymer Science
Parthiv M. Trivedi, Chandra Prakash Gocher, Vijai Balachandran, Virendra Kumar Gupta
Summary: This study reports the synthesis of polypropylene products using a MgCl2 supported multidentate Ziegler-Natta (Z-N) pre-catalyst. Compared to conventional bidentate Z-N pre-catalysts, the multidentate Z-N pre-catalyst showed better hydrogen response and controlled isotacticity in propylene polymerization. Melt rheology analysis showed higher modulus values for ultra-high molecular weight isotactic polypropylene (UHMWiPP) compared to medium molecular weight PP resins. GPC analysis revealed a medium to broad unimodal molecular weight distribution (MWD) for PP products produced with the multidentate Z-N pre-catalyst system.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Chemistry, Organic
Vinita Yadav, Sayali G. Jagtap, Ekambaram Balaraman, Santosh B. Mhaske
Summary: A novel method for the synthesis of N-substituted indoles under additive and base-free conditions is reported. The method utilizes a one-pot cascade approach with water as the only stoichiometric byproduct. The catalytic system used in this transformation exhibits high efficiency. A diverse range of N-alkylated indoles can be synthesized using various substrates.
Article
Chemistry, Organic
Akash Mondal, Abhijith Karattil Suresh, Ganesan Sivakumar, Ekambaram Balaraman
Summary: This research reveals a sustainable and affordable method for the direct synthesis of (deuterated) N-methyl/ethyl amines from nitroarenes. The method is catalyzed by a single-site manganese catalyst and involves tandem dehydrogenation, transfer hydrogenation, and borrowing hydrogenation. This catalytic protocol shows high selectivity and provides a convenient approach for the large-scale synthesis of a series of N-CH3/N-CD3 aniline derivatives with excellent functional group tolerance.
Article
Chemistry, Organic
Vishakha Goyal, Tarun Bhatt, Chitrarekha Dewangan, Anand Narani, Ganesh Naik, Ekambaram Balaraman, Kishore Natte, Rajenahally V. Jagadeesh
Summary: This study reports the catalytic utilization of methanol as a hydrogen source for the reduction of various functional organic compounds. The use of a commercially available Pt/C catalyst enables the transfer hydrogenation of nitroarenes, olefins, and carbonyl compounds. The Pt/C catalytic system shows practicability in terms of catalyst recycling and reusability, as well as reaction upscaling, along with the N-methylation and N-alkylation of anilines.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
K. Vipin Raj, Virendra Kumar Gupta, Kumar Vanka
Summary: Ziegler-Natta (Z-N) systems are efficient heterogeneous catalysts for the production of isotactic polypropylene and polyethylene. External donors significantly improve the stereoselectivity of polymerization by coordinating at vacant sites created by the extraction of internal donors. DFT studies show that the bite difference problem between internal and external donors can be overcome by the formation of adducts between external alkoxysilane donors and AlEt2Cl in the Z-N systems, which enhances the stereoselectivity of the catalysts.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Mechanics
Vincenzo Ianniello, Salvatore Costanzo, Rossana Pasquino, Giovanni Ianniruberto, Virendra K. Gupta, Lucas Stieglitz, Bernhard Rieger, Theo Tervoort, Nino Grizzuti
Summary: This study examines the possibility of determining the molecular weight distribution (MWD) of linear ultrahigh molecular weight (UHMW) polypropylene (PP) using rheology. Various UHMWPP samples are analyzed using linear viscoelastic measurements and creep experiments to calculate the terminal relaxation. The results are compared with gel permeation chromatography (GPC) data using a mixing rule based on the relaxation modulus. Material parameters governing the stress relaxation of PP are estimated from lab-made UHMWPP samples, and this information is used to predict the MWD of other samples. The direct and inverse problems of obtaining rheological responses from MWD and vice versa are solved, showing satisfactory agreement between calculated and measured MWD.
Article
Engineering, Chemical
Ritesh J. Dhanorkar, Subhra Mohanty, Ashok Misra, Virendra Kumar Gupta
Summary: Nanoemulsion polymerization is a new process for synthesizing specialty-purpose latexes. Styrene and 1,4-butadiene polymerization were demonstrated using a nanoemulsion-based method. Conventional emulsifiers were used to prepare base emulsions with small particle sizes. The use of nanoemulsion improved the efficiency and quality of emulsion, leading to higher productivity. These latexes have high molecular weight polymers with small particle sizes, making them ideal for coating applications. A comparison was made between nanoemulsion-based polymer and conventional macroemulsion-based product.
POLYMER ENGINEERING AND SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Reshma Babu, Subarna Sukanya Padhy, Rohit Kumar, Ekambaram Balaraman
Summary: Sustainable chemical production requires the development of coherent and robust catalytic systems based on earth-abundant transition metals. This study explores a novel tandem reaction that converts cyclic and acyclic diazo compounds into valuable amines using a single-site molecular manganese complex as the catalyst. The reaction involves dehydrogenation, transfer hydrogenation, and borrowing hydrogenation strategies, and utilizes renewable feedstocks such as alcohols. The synthetic application of this approach in pharmaceutical synthesis and the production of N-CH3/CD3 derivatives is also demonstrated.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Review
Polymer Science
Sangeetha Karthikeyan, Virendra Kumar Gupta
Summary: Highly reactive polyisobutylene (HRPIB) is a crucial industrial polymer used extensively as additives for lubricants, fuels and polymers. This review focuses on the synthetic processes of HRPIB, particularly the carbocationic approach, organometallic catalyst systems and carbocationic polymerization with Lewis acid-based chain transfer promoting catalysts. The use of Lewis acid complexes with ionic liquids has shown great potential in producing HRPIB with desired characteristics. Future advancements need to consider economic and environmentally-friendly approaches to ensure valuable commercial processes and HRPIB products.
JOURNAL OF POLYMER RESEARCH
(2023)
Article
Chemistry, Organic
Olutayo N. Farinde, Vanaparthi Satheesh, Kendra K. Shrestha, Carmen R. Rhinehalt, Vinod G. Landge, Michael C. Young
Summary: Cinnamylamines are important components of many drugs targeting G protein-coupled receptors. Existing methods for synthesizing 3,3-diarylallylamines often involve a multistep process that includes poorly-selective Wittig addition and direct aryl addition to N-protected cinnamylamines using aryl iodides which leads to decreased selectivity. However, by using aryl boronic acids, the yield and selectivity can be improved.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Madhu Nallagangula, Murugan Subaramanian, Rohit Kumar, Ekambaram Balaraman
Summary: In recent years, the borrowing hydrogen (BH) and interrupted borrowing hydrogen (IBH) strategies have gained significant attention for their efficient and sustainable synthesis of diverse building blocks. These approaches offer advantages such as use of feedstock chemicals, high atom economy, no pre-activation of substrates, and water as the only by-product. This review article focuses on the recent advances in the IBH strategy and its application in sustainable chemical synthesis, particularly in C-C bond formation, synthesis of 3,3'-bisindolylmethanes, alpha-branched ketones/diketones, and regioselective alkylation of N-heterocycles.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Reshma Babu, Subarna S. Padhy, Ganesan Sivakumar, Ekambaram Balaraman
Summary: Sustainable chemical production requires new catalysts and technologies, and the development of robust catalytic systems based on plentiful transition metals is crucial.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Organic
Vinod G. Landge, Audrey L. Bonds, Thandazile A. Mncwango, Carolina B. Mather, Yasaman Saleh, Hunter L. Fields, Frank Lee, Michael C. Young
Summary: The transition metal-catalyzed Mizoroki-Heck reaction is an important method for synthesizing C-C bonds to produce pharmaceuticals. However, traditional approaches were not compatible with free amines due to oxidation or side reactions. This study presents a palladium-catalyzed selective monoarylation method for free allylamines, which is applicable to primary, secondary, and tertiary amines.
ORGANIC CHEMISTRY FRONTIERS
(2022)
