Article
Chemistry, Organic
Xiangjie Chen, Yi An, Guangfen Du, Yujie Zhao, Lin He, Jixing Zhao, Shi-Wu Li
Summary: This study established a method for asymmetric catalytic vinylogous Michael addition of 2-methyl-3,5-dinitrobenzoates to unsaturated ketones using chiral rhodium catalysts. This strategy successfully synthesized a variety of optically pure compounds containing imidazole and 3,5-dinitrobenzene skeletons.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Jen-Yu Kuan, I-Ting Chen, Hsuan Lin, Jeng-Liang Han
Summary: We have developed a substrate-dependent, regio- and stereocontrolled diversity-oriented organocatalytic vinylogous Michael addition/cyclization cascade of 2-alkylidene indane-1,3-diones with enals, using secondary amines as the catalyst. This method allows for the selective synthesis of spiroindane-1,3-diones, tetrahydrofluoren-9-one derivatives, and benzofused oxabicyclo[3.3.1]nonanes. Plausible catalytic pathways have been proposed, and DFT calculations have clarified the mechanisms involved.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Alexey A. Tsygankov, Denis Chusov
Summary: By using a fluoride anion source, well-known transition metal catalysts can be transformed into high-performance versions, increasing catalytic activity, particularly in reactions such as asymmetric cyanation of aldehydes, asymmetric Michael addition, and synthesis of cyclic carbonates.
Article
Chemistry, Multidisciplinary
Matteo Balletti, Enrico Marcantonio, Paolo Melchiorre
Summary: Reported in this study is a rare example of asymmetric catalytic functionalization of enals at the remote gamma-position through a radical pathway. This process utilizes the synergistic actions of two distinct organocatalysts and requires visible light irradiation.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Ana De Oliveira Silva, Jordan L. Harper, Katherine N. Fuhr, Roger A. Lalancette, Paul Ha-Yeon Cheong, Stacey E. Brenner-Moyer
Summary: This study successfully synthesized gamma-epimeric enals via Claisen rearrangement, leading to enantioenriched products. Different types of enals are suitable substrates, and the products can be readily converted into pyrrolidines or cyclopentenols. Furthermore, a reactive dienamine intermediate was isolated, fully characterized, and converted to product under reaction conditions. The product configuration is determined by a directing C-H···π interaction in the transition state.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Irma Garcia-Monzon, Jorge Borges-Gonzalez, Tomas Martin
Summary: The heterogenization of homogeneous catalysts onto a solid support is a crucial step towards sustainable chemistry. In this study, we developed a series of polymer-supported tetrahydropyran-based hybrid dipeptides as active catalysts for the enantioselective Michael addition of aldehydes to beta-nitrostyrenes. The optimal anchor position and orientation between the catalyst and solid support, as well as the linker length, were carefully designed to enhance the catalytic efficiency. These supported catalysts exhibited high yields and enantiomeric excesses, and detailed deactivation studies provided important insights for prolonging their useful life.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Jose M. Odriozola, Jesus Razkin, Benat Lorea, Antonia Mielgo, Jesus M. Garcia, Mikel Oiarbide, Claudio Palomo
Summary: In this study, it is demonstrated that the internal H-bonding self-activation in alpha'-hydroxy enones allows for smooth reaction with enolizable aldehydes using commercially available aminocatalysts, resulting in good yields and high enantioselectivity of the adducts. The conversion of the ketol moiety of these adducts into aldehyde, ketone and carboxylic acid functionalities provides an indirect, unified entry to products derived from acrolein, alkyl-vinyl ketones, and acrylates, respectively.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Applied
Gianluca Casotti, Vincenzo Rositano, Anna Iuliano
Summary: Stabilised arylzinc iodide prepared by direct insertion of zinc into aryl iodides, were successfully applied as nucleophiles in the Hayashi Rh-catalysed enantioselective conjugate addition to enones, with high yields and 99% ee of the addition product. The general applicability of the protocol was confirmed by using different arylzinc iodides and enones, as well as organometallic reagents with both halogen and electrophilic groups.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Physical
Yiqi Ren, Maodi Wang, Qihua Yang, Junfa Zhu
Summary: The development of chiral solid catalysts using unconventional strategies is crucial for efficient heterogeneous asymmetric catalysis. The study presents a chiral solid catalyst, chiral diamine modified Ni/SiO2, for asymmetric Michael addition. The experimental results demonstrate that the peripheral Ni sites in close contact with SiO2 support are likely to be the active sites.
Article
Chemistry, Multidisciplinary
Subhasis Paul, Dario Filippini, Mattia Silvi
Summary: The intermolecular addition of alkyl radicals to alkenes is a fundamental process in organic chemistry but is limited by electron deficiency of the alkene component. In this study, a polarity transduction strategy is introduced to overcome this electronic limitation. Vinyl sulfonium ions react with carbon-centered radicals to provide products that are otherwise inaccessible. The generality of this strategy is demonstrated through the derivatization of unmodified complex bioactive molecules.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Sanjay Singh, Ravi Saini, Ravi P. Singh
Summary: An unprecedented organocatalyzed asymmetric vinylogous Michael reaction with excellent enantiomeric ratio and yield has been reported. The remarkable selectivity is attributed to the hydrogen bonding ability of the catalyst. The reaction is versatile and practical for the synthesis of various gamma-functionalized coumarin derivatives.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Li-Xia Liu, Wen-Jun Huang, Qing-Xian Xie, Bo Wu, Chang-Bin Yu, Yong-Gui Zhou
Summary: The research proposed a new strategy for dynamic kinetic resolution, successfully achieving enantioselective separation of flavonoid compounds and forming two stereogenic centers, providing a new way for organic synthesis.
Article
Chemistry, Organic
Ruslan A. Kovalevsky, Maxim Smirnov, Alexander S. Kucherenko, Kseniya A. Bykova, Elizaveta Shikina, Sergei G. Zlotin
Summary: In this study, 2-nitroallylic carbonates were used for the first time as promising biselectrophilic C3 synthons. They reacted with kojic acid derivatives in a bifunctional squaramide catalyzed asymmetric domino reaction, yielding nitro compounds that contain two hydroxypyranone units. The reaction products undergo noncatalytic epimerization at the carbon atom next to the nitro group. A plausible mechanism of the epimerization based on reversible formation of intermediate aci-nitro compound is proposed. The double addition products were transformed into configurationally stable acetates and chiral nitro glutarates, which are promising precursors for chiral amino glutaric acid derivatives.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Kenya Tamaribuchi, Jiaqi Tian, Kengo Akagawa, Kazuaki Kudo
Summary: Enantioselective Michael addition of beta-dicarbonyl compounds towards nitroalkenes was achieved using an immobilized, N-terminal-guanidinylated peptide catalyst. Various nucleophiles and electrophiles were employed, with the resin-supported catalyst being recyclable for five cycles. This method shows promise for industrial applications.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Wei-Dong Lu, Yu Zheng, Zhi-Peng Zhang, Hong-Bin Chen, Kai Chen, Hao-Yue Xiang, Hua Yang
Summary: In this study, a visible-light-induced palladium-catalyzed desaturation/sulfonation cascade is reported, providing a concise method for the synthesis of highly valuable 4-sulfonyltetrahydropyridine scaffolds from inexpensive and readily available piperidine derivatives with sodium sulfinates. The success of this transformation relies on the well-designed sequence of palladium-mediated 1,5-hydrogen atom transfer/β-hydride elimination/allylic sulfonation process, highlighting the potential of orchestrating synthetic events through rational utilization of varied catalytic modes.
Review
Chemistry, Multidisciplinary
Rosa Lopez, Claudio Palomo
Summary: This Minireview highlights the limited but significant catalytic methods for the generation of planar chirality in strained molecules, and serves as an inspiration for the development of new unconventional procedures in the future.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Valeria Nori, Arianna Sinibaldi, Giuliana Giorgianni, Fabio Pesciaioli, Francesca Di Donato, Emanuele Cocco, Alessandra Biancolillo, Aitor Landa, Armando Carlone
Summary: The development of a rational approach for enantioselective enamine-catalysed addition of masked acetaldehyde to nitroalkenes has helped to replace the use of chloroform. The use of water as a reaction medium in this protocol improves the industrial relevance of accessing important pharmaceutical intermediates. The success of this research is attributed to the chemometrics-assisted 'Design of Experiments' (DoE) optimisation, which allows a rational exploration of the chemical space.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Inorganic & Nuclear
Jiang Liu, Weikang Lin, Alexander E. Sorochinsky, Greg Butler, Aitor Landa, Jianlin Han, Vadim A. Soloshonok
Summary: Trifluoromethoxy-containing molecules are a highly promising group of biologically active compounds that are still underdeveloped. This article discusses five known pharmaceuticals and five marketed agrochemicals featuring trifluoromethoxy group, providing detailed information on their chemical synthesis and general aspects of biological activity.
JOURNAL OF FLUORINE CHEMISTRY
(2022)
Review
Chemistry, Organic
Silvia Vera, Ane Garcia-Urricelqui, Antonia Mielgo, Mikel Oiarbide
Summary: Thiourea- and squaramide-based bifunctional base catalysts have become a powerful tool for enantioselective transformations in asymmetric catalysis. Recent developments have focused on incorporating additional H-bond donor sites into the catalyst structure, resulting in more active and selective catalysts. This review presents the pioneering ideas and recent contributions to the field, organized according to the nature of the additional H-bond donor functionality, and discusses the advantages, limitations, and prospects of these new multifunctional catalysts.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
David Ibarra, Luisa Garcia-Fuentevilla, Gabriela Dominguez, Raquel Martin-Sampedro, Manuel Hernandez, Maria E. Arias, Jose I. Santos, Maria E. Eugenio
Summary: The usage of laccases is a sustainable and environmentally friendly approach to modifying the Kraft lignin structure for use in certain applications. However, the inherent structure of Kraft lignin, as well as that resulting from laccase modification, still presents challenges for fundamental comprehension and successful lignin valorization.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Organic
Leire Villaescusa, Iker Hernandez, Laura Azcune, Ainhoa Rudi, Jose M. Mercero, Aitor Landa, Mikel Oiarbide, Claudio Palomo
Summary: The catalytic addition of hydantoin surrogates to rigidified vinylidene bis(sulfone) reagents was achieved, overcoming the unreactivity of commonly used beta-substituted vinylic sulfones. The resulting adducts were transformed into enantioenriched 5,5-disubstituted hydantoins through hydrolysis and reductive desulfonylation processes, offering new structures for potential bioassays. Density functional theory studies provided insights into the observed reactivity and stereoselectivity trends.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Eider Dunabeitia, Aitor Landa, Rosa Lopez, Claudio Palomo
Summary: The study demonstrates the capability of bicyclic acylpyrrol lactims to act as pronucleophiles and form carbon-carbon bonds under organocatalytic conditions, leading to the synthesis of chiral pyrrolodiketopiperazines. The use of ureidoaminal-derived Bronsted bases in the Michael addition to nitroolefins allows for the generation of heterocyclic scaffolds with a high degree of skeletal diversity.
Article
Polymer Science
Luisa Garcia-Fuentevilla, Gabriela Dominguez, Raquel Martin-Sampedro, Manuel Hernandez, Maria E. Arias, Jose I. Santos, David Ibarra, Maria E. Eugenio
Summary: This study investigated the polymerization of kraft lignin using different laccase sources and analyzed the influence of various variables. The response surface methodology was used to predict and characterize the behavior of the output variables. The results demonstrated that laccase could promote lignin polymerization, with enzyme concentration being the most influential variable.
Article
Chemistry, Multidisciplinary
Mikel Oiarbide, Claudio Palomo
Summary: Chiral Bronsted base (BB) catalyzed asymmetric transformations are important for synthesis. These transformations involve transiently generated enolate intermediates that react with a variety of electrophiles. Our group focused on developing BB-catalyzed asymmetric reactions of enolizable carbonyl substrates, with an additional challenge of controlling site-selectivity. This account illustrates the opportunities and challenges of these methods, with a focus on generating quaternary carbon stereocenters. New bifunctional BB catalysts and achiral templates were developed during this process.
Article
Biochemistry & Molecular Biology
Laura Sanchez-Sanchez, Javier Garcia, Roberto Fernandez, Ekaterina Noskova, June Egiguren-Ortiz, Marina Gulak, Eneko Ochoa, Antonio Laso, Mikel Oiarbide, Jose Ignacio Santos, Maria Fe Andres, Azucena Gonzalez-Coloma, Albert Adell, Egoitz Astigarraga, Gabriel Barreda-Gomez
Summary: Cannabis has been used as a palliative therapy for cancer treatment due to its beneficial effects on pain and nausea. The main compounds in Cannabis, THC and CBD, exert their actions through receptor-mediated and non-receptor-mediated mechanisms, affecting the formation of reactive oxygen species. Evidence suggests a potential antitumor effect of cannabinoids in different types of cancer, although controversial results limit their implementation.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)