Article
Chemistry, Physical
Fangfang Guo, Jiean Chen, Yong Huang
Summary: Recently, chiral N-heterocyclic carbenes (NHCs) have been established as powerful catalysts for enantioselective bond-forming processes via noncovalent interactions. A bifunctional NHC with an embedded hydrogen-bonding motif has been reported in this study, showing remarkable tolerance of various Michael acceptors in an asymmetric aza-conjugate addition reaction, with catalytic efficiency far exceeding that of the benchmark tertiary amine-thiourea scaffold.
Review
Chemistry, Multidisciplinary
Cheng Niu, Da-Ming Du
Summary: This review highlights the recent advancements in sulfa-Michael addition-triggered cascade reactions for the stereoselective synthesis of sulfur-containing compounds. It discusses various types of reactions, including sulfa-Michael/aldol, sulfa-Michael/Henry, sulfa-Michael/Michael, sulfa-Michael/Mannich and some sulfa-Michael triggered multi-step processes. The review also introduces reaction mechanisms and derivatization experiments.
Article
Chemistry, Organic
Pavit Kumar Ranga, Feroz Ahmad, Prashant Nager, Prabhat Singh Rana, Ramasamy Vijaya Anand
Summary: The catalytic application of bis(amino)cyclopropenium ion in conjugate addition reactions has been investigated, with the hydrogen atom on the cyclopropene ring acting as a hydrogen-bond donor catalyst. Experimental studies have verified that the C-H hydrogen in the cyclopropene ring is solely responsible for catalyzing these transformations, activating the carbonyl group of p-quinone methide through hydrogen bonding.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Laura A. Bryant, Kenneth Shankland, Hannah E. Straker, Callum D. Johnston, Nicholas R. Lees, Alexander J. A. Cobb
Summary: The article describes a rare organocatalytic intramolecular cyclization of resorcinols with a high enantioselectivity using a specific organocatalyst. The obtained bicyclic resorcinols show excellent utility in the synthesis of cannabinoid-like compounds, and exhibit anticonvulsant activity.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
En Li, Jiean Chen, Yong Huang
Summary: The Michael reaction is an important method for preparing functional molecules with a β-stereogenic center. However, the enantioselective seleno-Michael addition is still poorly explored. In this study, a highly enantioselective Michael addition reaction of alkyl selenols to enones was reported, introducing a Se atom asymmetrically to an electron-deficient double bond. A chiral bifunctional N-heterocyclic carbene (NHC)/thiourea catalyst was developed and showed remarkable selectivity in delivering chiral β-seleno ketones.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Amol B. Gorde, Anas Ansari, Ramesh Ramapanicker
Summary: New molecules were designed and synthesized to improve the catalytic ability of the catalyst, resulting in high catalytic activity and stereoselectivity under optimized conditions. The studies showed high yields of Michael adducts with excellent enantioselectivities and diastereoselectivities in a wide range of aldehydes and beta-nitrostyrenes.
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, Applied
Andrea Guerrero-Corella, Miguel A. Valle-Amores, Alberto Fraile, Jose Aleman
Summary: An asymmetric organocatalytic aza-Michael addition reaction of ketimines to nitroolefins is described, utilizing 2-hydroxybenzophenone imine to improve the enantioselective addition of N-centered nucleophiles to nitroalkenes. The versatility of the process is demonstrated under both batch and flow conditions, resulting in the synthesis of a wide variety of nitroamine derivatives with excellent yields and enantioselectivities. Additionally, this methodology was successfully applied to the formal synthesis of VNI, a drug-like scaffold for the treatment of Chagas disease.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Eugenia Marques-Lopez, Isaac G. Sonsona, Miryam Garces-Marin, M. Concepcion Gimeno, Raquel P. Herrera
Summary: In this study, the potential of phosphites as nucleophiles for the asymmetric synthesis of chiral chromene derivatives was explored. By employing asymmetric organocatalyzed phospha-Michael addition, chiral chromenylphosphonates were synthesized using a bifunctional squaramide. The optimized protocol provided good reactivity with yields of up to 95% and chiral products with an enantiomeric excess of up to 98%.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Biochemistry & Molecular Biology
Jae Ho Shim, Seok Hyun Cheun, Hyeon Soo Kim, Deok-Chan Ha
Summary: The study utilized thiourea as an organocatalyst to promote enantioselective Michael addition reaction between isobutyraldehydes and maleimides in water, achieving high yield and enantioselectivity. The solvent effect was explained by theoretical calculations suggesting the participation of a hydrogen bond activated CF3 substituent of the catalyst by surrounding water molecules, enabling low catalyst loading in organic reactions of chiral substances for pharmaceutical applications.
Article
Chemistry, Multidisciplinary
Gorka Garay, Josebe Hurtado, Manuel Pedron, Lorena Garcia, Efraim Reyes, Eduardo Sanchez-Diez, Tomas Tejero, Luisa Carrillo, Pedro Merino, Jose L. Vicario
Summary: We have demonstrated the catalytic and enantioselective rearrangement of vinylcyclopropane-cyclopentene, using (vinylcyclopropyl)acetaldehydes as starting materials and enamine intermediates for activation. The reaction involves the generation of a donor-acceptor cyclopropane, leading to the formation of an acyclic iminium ion/dienolate intermediate where stereochemistry is erased. The final cyclization step results in the stereocontrolled formation of various structurally distinct cyclopentenes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
David A. McLeod, Mathias Kirk Thogersen, Casper Larsen Barlose, Mette Louise Skipper, Erlaitz Basabe Obregon, Karl Anker Jorgensen
Summary: This study presents a novel enantioselective (8+3) cycloaddition reaction using a chiral bifunctional Bronsted base catalyst. The reaction leverages an anionic activation strategy and differs from typical Lewis-acid activation protocols. Experimental and computational results support the relevance of this reaction and its potential application in organic synthesis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Applied
Jasper S. Moehler, Lena K. Beiersdoerfer, Brenno Masina, Philipp Wechsler, Helma Wennemers
Summary: N-heterocyclic moieties are commonly found in pharmaceuticals and agrochemicals, but pose a challenge for metalorganic and organocatalytic transformations. This study presents tripeptide catalysts for stereoselective conjugate addition reactions between N-heterocyclic substituted aldehydes and electrophiles, achieving high yields and selectivities.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Review
Chemistry, Organic
Girija S. Singh
Summary: Asymmetric organic synthesis is crucial in drug development, with many functional group transformation reactions seeing significant progress under green conditions.
CURRENT ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Poorna Chandrasekhar Settipalli, Shaik Anwar
Summary: A [2+2+2] annulation reaction between cyclohexanone, beta-nitrostyrene and 2-arylidene-1,3-indanedione has been successfully carried out to obtain multisubstituted spiro trans-decalinol derivatives at room temperature. This reaction process exhibits high chemical yields and excellent diastereoselectivity, resulting in the formation of multiple bonds and stereocenters through the Michael/nitro-Michael/Aldol process.
CHEMICAL COMMUNICATIONS
(2022)
Review
Biochemistry & Molecular Biology
Ana M. F. Phillips, Armando J. L. Pombeiro
CURRENT MEDICINAL CHEMISTRY
(2019)
Article
Environmental Sciences
Carlos M. H. Ferreira, Catia A. Sousa, Ines Sanchis-Perez, Sandra Lopez-Rayo, Maria Teresa Barros, Helena M. V. M. Soares, Juan J. Lucena
SCIENCE OF THE TOTAL ENVIRONMENT
(2019)
Review
Chemistry, Multidisciplinary
Ana Maria Faisca Phillips, M. Fatima C. Guedes da Silva, Armando J. L. Pombeiro
FRONTIERS IN CHEMISTRY
(2020)
Article
Biochemistry & Molecular Biology
Claudia D. Raposo, Cristiano A. Conceicao, M. Teresa Barros
Review
Chemistry, Physical
Ana Maria Faisca Phillips, Maria de Fatima C. Guedes da Silva, Armando J. L. Pombeiro
Review
Chemistry, Inorganic & Nuclear
Ana Maria Faisca Phillips, Hongyi Suo, Maria de Fatima C. Guedes da Silva, Armando J. L. Pombeiro, Wen-Hua Sun
COORDINATION CHEMISTRY REVIEWS
(2020)
Review
Biochemistry & Molecular Biology
Claudia D. Raposo, Andre B. Canelas, M. Teresa Barros
Summary: Lectins, a class of proteins responsible for various biological roles, can be targeted for drug delivery systems due to their ability to bind to carbohydrates. Research has identified specific carbohydrate recognition by lectin receptors and their distribution within the human body.
Review
Chemistry, Physical
Ana Maria Faisca Phillips, Martin H. G. Prechtl, Armando J. L. Pombeiro
Summary: Chiral bifunctional dual H-bond donor catalysts have become essential in organocatalysis, promoting various reactions with high yields and excellent stereoselectivities. Understanding their mechanisms and the origin of stereoselectivity can guide the development of more efficient catalysts for new transformations.
Editorial Material
Chemistry, Multidisciplinary
Carina I. C. Crucho, Maria Teresa Barros
Summary: This article discusses the rich chemistry of sucrose, a carbohydrate that enhances the sweetness of life.
Review
Chemistry, Organic
Ana Maria Faisca Phillips, Armando J. L. Pombeiro
Summary: Catalytic enantioselective electrochemical synthesis, as an efficient and sustainable approach, has recently gained attention in obtaining chiral, non-racemic molecules. Fine-tuning of reaction conditions using minute differences in potential allows for high chemoselectivities. Although the number of methods is limited, they enable a variety of bond-forming reactions with high yields and enantioselectivities. This review surveys literature published in the past four years.
SYNTHESIS-STUTTGART
(2023)
Article
Polymer Science
Hongyi Suo, Ana Maria Faisca Phillips, Manas Satrudhar, Luisa M. D. R. S. Martins, Maria de Fatima G. da Silva, Armando J. L. Pombeiro, Mingyang Han, Wen-Hua Sun
Summary: A series of vanadium(V) aroylhydrazine-arylolates have been found to be employed in ethylene polymerization to produce ultra-high molecular weight polyethylene (UHMWPE), and the significant effects of different cocatalysts on the reaction have been revealed.
JOURNAL OF POLYMER SCIENCE
(2023)
Review
Multidisciplinary Sciences
Ana Maria Faisca Phillips, Armando J. L. Pombeiro
Summary: Atropisomers, which are stereoisomers hindered in their rotation due to steric interactions or electrostatics, exhibit unique characteristics and can be found in various applications. The synthesis of atropisomers containing C-N and N-N axes of chirality has become a hot topic in research, focusing on sustainable synthesis using achiral materials and organocatalysts under mild conditions. This review provides an overview of recent achievements in this field.
Review
Chemistry, Physical
Ana Maria Faisca Phillips, Armando J. L. Pombeiro
Summary: Hantzsch esters have emerged as versatile reagents for enantioselective organic transformations in the last century. They can selectively reduce various multiple bonds, such as C=C and C=N, as hydride transfer agents under mild reaction conditions. Additionally, they are effective for the dearomatization of heteroaromatic substances and can participate in cascade processes. In recent years, they have also been employed in photoredox reactions, acting as sacrificial electron and hydrogen donors, as well as alkyl or acyl radical transfer agents.
Article
Chemistry, Physical
Ana Maria Faisca Phillips, Armando J. L. Pombeiro
Summary: Nitrogen-containing heterocycles, such as morpholin-2-ones, are important structural elements in biologically active substances and can serve as synthetic intermediates. A new method for regioselective cross-dehydrogenative coupling between morpholinones and cyclic imides was developed using copper(I) chloride as a metal catalyst and molecular oxygen as the oxidant. The C-N coupled products were obtained in high yields under mild conditions, and they have potential applications in the development of biologically active compounds as well as functionalized polymers or PROTACs.
Review
Chemistry, Organic
Ana Maria Faisca Phillips, Armando J. L. Pombeiro
ORGANIC & BIOMOLECULAR CHEMISTRY
(2020)
