Article
Chemistry, Physical
Viktoria Kozma, Zsolt Szakonyi, Gyorgy Szollosi
Summary: This study reveals the structural effects of beta-amino acids on the asymmetric Michael additions, including the impact of substituent bulkiness on selectivity, the beneficial arrangement of functional groups in cis isomers, and the influence of nitrogen substituents on reaction rate and enantioselectivity.
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, Multidisciplinary
Greta Vastakaite, Claudio E. Grunenfelder, Helma Wennemers
Summary: This study presents a tripeptide catalyst for the efficient and stereoselective synthesis of chiral succinimides via conjugate addition reactions between aldehydes and C-substituted maleimides. The catalyst exhibits high chemoselectivity and allows direct derivatization of the succinimides to access other chiral compounds.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
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, 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
Biochemistry & Molecular Biology
Dae Young Kim
Summary: A one-pot strategy has been developed for the synthesis of multisubstituted 3,4-dihydrocoumarins with high yields and excellent diastereoselectivity. This approach involves C-H oxidation and cyclization cascade reactions of 2-alkyl phenols and oxazolones in the presence of silver oxide and p-toluenesulfonic acid as catalysts.
Article
Chemistry, Applied
Haifeng Yu, Jian Mo, Xuemin Niu, Dashuang Luo, Guangbo Che
Summary: Switchable synthesis of 3-alkenyl succinimides and maleimides was achieved by adjusting reaction conditions. The Michael addition reaction of alpha-oxo ketene dithioacetals and maleimides using CH3SO3H in DCE at 120 degrees C resulted in 40-90% yields of 3-alkenyl succinimides. The oxidative cross-coupling reaction of alpha-oxo ketene dithioacetals with maleimides using Pd(OAc)(2) in DMF at 20 degrees C yielded 40-80% yields of 3-alkenyl maleimides. The method can be scaled up to gram scale without the need for directing groups on the substrates.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Biochemistry & Molecular Biology
Alejandro Torregrosa-Chinillach, Rafael Chinchilla
Summary: This study demonstrates the enantioselective synthesis of succinimides by the conjugated addition of ketones to maleimides, catalyzed by a simple primary amine-salicylamide. The reaction gives the desired compounds in good to excellent yields and with moderate to excellent enantioselectivities.
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
Chemistry, Multidisciplinary
Hui Zhang, Lihua Song, Weicheng Yuan, Xiaomei Zhang
Summary: A diastereo- and enantioselective aza-Mannich addition of oxazolones to alpha-amino sulfones has been developed using a tertiary amine-1-phenylethyl thiourea catalyzed by a cinchona-based structure. The reaction yielded azlactone adducts with high yields and moderate to excellent stereoselectivity. The absolute configuration of a product was determined by X-ray crystal structural analysis and a plausible reaction mechanism was proposed.
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.
Article
Chemistry, Physical
Viktoria Kozma, Gyorgy Szollosi
Summary: In this study, asymmetric Michael additions of 1,3-dicarbonyl compounds to N-substituted maleimides were carried out using primary amine-(thio)phosphoramide bifunctional chiral organocatalysts derived from optically pure C-2-symmetric 1,2-diamines. The results show that the addition of ethyl 2-fluoroacetoacetate using the thiophosphoramide catalyst derived from 1,2-diphenylethane-1,2-diamine afforded succinimides substituted with fluorine bearing quaternary carbon in high yields, good diastereomeric ratios and excellent enantiomeric excesses. The bulkiness of the N-substituent of the maleimide ring influenced mostly the conversions. Additionally, the thiophosphoramide catalyst was found efficient in the addition of ethyl 2-fluoroacetoacetate to beta-nitrostyrenes.
MOLECULAR CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Riccardo Conti, Anna Widera, Georgina Mueller, Csilla Fekete, Debora Thoeny, Frederik Eiler, Zoltan Benko, Hansjoerg Gruetzmacher
Summary: A simple and highly atom economic method has been found for preparing a wide range of photoinitiators adapted to specific fields of application. This method involves the addition of bis(mesitoyl)phosphine to activated carbon-carbon double bonds, using basic potassium or caesium salts as additives. Simple amine bases can also be used as catalysts, with tetramethylguanidine being a particularly outstanding catalyst.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Applied
Marta Meazza, Ramon Rios
Summary: This study describes the first synthesis of 2-alkenylquinolines from 2-allylquinolines and alpha,beta-unsaturated aldehydes. The reaction exhibits high regioselectivity and enantioselectivity, with a broad tolerance of functionalities in both the enal aromatic ring and the quinoline.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Vojtech Docekal, Tereza Koberova, Jan Hrabovsky, Andrea Vopalenska, Robert Gyepes, Ivana Cisarova, Ramon Rios, Jan Vesely
Summary: A new asymmetric organocatalytic cascade reaction was reported for the synthesis of enantiopure chiral boron dipyrromethenes (BODIPYs), with high isolated yields and enantiomeric excesses. The method showed synthetic versatility and was successfully applied to a series of additional transformations of the corresponding optically pure compounds.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Laura Bayes-Garcia, Shinichi Yoshikawa, Mercedes Aguilar-Jimenez, Chinami Ishibashi, Satoru Ueno, Teresa Calvet
Summary: The study revealed that the addition of talc particles promoted the crystallization of cocoa butter in a more stable form, serving as a polymorphic stabilizer. Talc not only increased the onset crystallization temperature logarithmically with increasing concentration, but also disrupted the ordered lamellar-plane direction of cocoa butter crystals at certain concentrations.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Biochemistry & Molecular Biology
Francisco Sanchez-Ferez, Joaquim Ma Rius-Bartra, Jose A. Ayllon, Teresa Calvet, Merce Font-Bardia, Josefina Pons
Summary: Aggregation between molecules is crucial for preventing aggregation-caused quenching. By incorporating ligands with different intra- and intermolecular interaction biases, absorption and emission properties can be compared. Properties of functional groups and coordination modes affect the photophysical properties.
Article
Chemistry, Physical
Jorge Macridachis, Laura Bayes-Garcia, Teresa Calvet
Summary: Differential scanning calorimetry and X-ray diffraction were used to study the mixing behavior of different triacylglycerol mixtures. The eutectic properties were mainly influenced by the crystallization, transformation, and melting behavior. The formation of solid solutions was determined by steric and kinetic effects. This research highlights the importance of the interaction between mixed-acid triacylglycerols and high-melting components in the solidification behavior of lipids.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Francisco Sanchez-Ferez, Xavier Solans-Monfort, Teresa Calvet, Merce Font-Bardia, Josefina Pons
Summary: Controlling the formation of desired product in the appropriate crystalline form is a fundamental breakthrough in crystal engineering. In this study, the formation of two concomitant polymorphs was observed, which originated from the Hg(II) cores and intermolecular associations, particularly indicated by Hg···π and π···π interactions. The selective synthesis of these polymorphs was successfully achieved by changing the synthetic conditions, and significant variations in solid-state photoluminescence were found due to differences in stability between the polymorphs.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Daniel Ejarque, Teresa Calvet, MercS Font-Bardia, Josefina Pons
Summary: The study synthesized four Zn(II) CPs involving alpha-acetamidocinnamic acid and 4,4'-bipyridine, and investigated their crystal structures and reversibility through different reactions and structural transformations. The research revealed the variations in properties and photoluminescence effects of these CPs due to structural differences and solvent/temperature influence.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Multidisciplinary
Ivana Miletto, Marta Meazza, Geo Paul, Maurizio Cossi, Enrica Gianotti, Leonardo Marchese, Ramon Rios, Marc Pera-Titus, Robert Raja
Summary: In this study, a designed N-heterocyclic carbene (NHC) catalyst was anchored on mesoporous and hierarchical supports of varying pore sizes to investigate the influence on the benzoin condensation of furfural. The characteristics of the anchored catalysts were examined to rationalize their stability and recyclability using molecular dynamics simulations. The results showed that the catalysts maintained quantitative yields (99%) and complete recyclability after multiple cycles, validating the design rationale.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Applied
Albert Martinez-Segura, Javier Eusamio, Yaiza M. Medina, Katherine Ariz, Albert Gutierrez, Joan Albert, Jaume Granell, Merce Font-Bardia, Arnald Grabulosa
Summary: Cycloruthenated complexes C1-C5 have been synthesized cleanly by the reaction of N-(benzylidene)benzylamines (p-RC6H4CH=NCH2C6H5; R = Cl, H, NO2, F, OMe) with [RuCl2(eta(6)-p-cymene)](2) and potassium acetate. The process exhibits complete regioselectivity, yielding the endo-derivative regardless of the substituent on the aromatic ring. The enantiopure imines (R-C)-p-RC6H4CH=NCHMeC10H7 (R = Cl, H) can also form five-membered endo-metallacycles C6 and C7 under similar conditions. The crystal structures of all seven metallated compounds have been determined by X-ray diffraction. These complexes serve as effective catalyst precursors for the transfer hydrogenation of acetophenone and benzophenone, with complex C7 achieving up to 77% enantiomeric excess at room temperature.
APPLIED ORGANOMETALLIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Daniel Ejarque, Teresa Calvet, Merce Font-Bardia, Josefina Pons
Summary: The study investigates the effect of small differences in organic ligands on the arrangement of coordination polymers (CPs). Reactions between Cd(OAc)2middot2H2O, alpha-acetamidocinnamic acid (HACA), and various N,N-donor spacers with increasing length and additional functionalities have been carried out successfully. The crystal structures of the resulting CPs have been elucidated, showing a family of ladder-type 1D CPs. UV-Vis and photoluminescence measurements demonstrate their blue-emitting properties.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Chemistry, Inorganic & Nuclear
Daniel Ejarque, Teresa Calvet, Merce Font-Bardia, Josefina Pons
Summary: The rational design of heterometallic compounds bearing s-block metal ions has been achieved by designing coordinating pockets with different sizes and/or donor atoms. The successful synthesis of a heterometallic compound with Ca(II) ion and the exploration of its application as a template for coordination polymers were discussed. The solid-state UV-Vis and photoluminescence of the compound were compared with a homometallic compound.
Article
Chemistry, Multidisciplinary
Francisco Sanchez-Ferez, Xavier Solans-Monfort, Teresa Calvet, Merce Font-Bardia, Josefina Pons
Summary: A new double-stranded staircase Hg(i) supramolecular assembly is formed, composed of 2D corrugated sheets supported by Hg(i)MIDLINE HORIZONTAL ELLIPSISOdioxole and HgMIDLINE HORIZONTAL ELLIPSIS pi interactions. This assembly is a result of the comproportionation reaction between Hg(ii) and Hg(0) species in DMF solvent.
Article
Chemistry, Multidisciplinary
Daniel Ejarque, Teresa Calvet, Merce Font-Bardia, Josefina Pons
Summary: This study systematically investigated the synthesis of fluorescent coordination complexes using Cd(II) ion and various pyridine ligands. The results showed that the fluorescence enhancement effect and the electronegativity of Cd(II) ion helped to prevent fluorescence quenching.
