Review
Chemistry, Organic
Thomas C. Nugent, Alice E. Vos, Ishtiaq Hussain, Hussein Ali El Damrany Hussein, Falguni Goswami
Summary: This study provides an extensive introduction to amine-catalyzed aldol reactions with enantioselectivity for non-experts. It covers methodology limitations, mechanisms, physical-mechanical aspects, and considerations for ketone substrates. The study highlights 172 catalysts and provides experimental data for various ketone substrates. It also discusses the best reaction conditions and product formation for specific substrates. This research enables the selection of suitable reaction methods for given substrates and allows the targeted construction of substrates for selective product formation.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Nanoscience & Nanotechnology
Miguel Sanchez-Fuente, Alberto Lopez-Magano, Alicia Moya, Ruben Mas-Balleste
Summary: Condensation of BINAPO-(PhCHO)(2) and 1,3,5-tris(4-aminophenyl)benzene(TAPB) leads to a new imine-based chiral organic material (COM) that can be post-functionalized through reductive transformation of imine linkers to amines. Although the imine-based material is not stable enough to be used as a heterogeneous catalyst, the reduced amine-linked framework can be efficiently utilized in asymmetric allylation of various aromatic aldehydes. The obtained yields and enantiomeric excesses are comparable to those observed for the molecular BINAP oxide catalyst, with the added advantage of recyclability offered by the amine-based material.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Organic
Venkati Bethi, Syeda Bakhtawar Zahra, Bapuaro D. Rupanawar, Fujie Tanaka
Summary: This article describes the regioselective aldol reactions of beta-methyl-substituted cyclic enone derivatives with isatins using a catalyst system composed of DBU, pyrrolidine, and DMSO. The reactions resulted in aldol products with bond formation at the methyl group of the beta-methyl-substituted cyclic enone derivatives. This method selectively affords gamma-position-reacted aldol products, expanding the scope of concisely synthesized 3-substituted 3-hydroxyoxindole derivatives.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Isaac G. Sonsona, Andrea Vicenzi, Marco Guidotti, Giorgiana Denisa Bisag, Mariafrancesca Fochi, Raquel P. Herrera, Luca Bernardi
Summary: The study demonstrates the improved selectivity of an asymmetric aldol reaction by replacing part of the catalyst, and identifies the most suitable reaction conditions. However, these conditions seem to be limited to oxindoles bearing a 3-substituent of funapide.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Maxim Smirnov, Alexander S. Kucherenko, Ilya D. Gridnev, Alexander A. Korlyukov, Sergei G. Zlotin
Summary: Biomass derived gamma-pyrone-2-carbaldehydes were used as a robust platform for carrying out organocatalytic asymmetric cross-aldol reactions with high yield and excellent stereoinduction. The origins of efficient stereoinduction were revealed by quantum-chemical calculations, and the products were successfully converted to synthetically useful chiral compounds.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Medicinal
Gabriela Huelgas, Ratnasamy Somanathan, Julio M. Hernandez Perez, Haydee Rojas Cabrera, Maximiliano de la Higuera Macias, Alejandra Dominguez-Huerta, Rocio Sabala, Cecilia Anaya de Parrodi
Summary: This study synthesized novel organic compounds, and successfully carried out highly enantioselective and diastereoselective reactions using organocatalysts under solvent-free conditions in the presence of water, achieving effective stereoselective induction.
Article
Chemistry, Multidisciplinary
Yusaku Yoshiwara, Shunsuke Kotani, Makoto Nakajima
Summary: The asymmetric catalytic transformations of N-unprotected cyclic carboxyimides provide a direct route to access a variety of biologically valuable chiral compounds, such as succinimides, hydantoins, oxazolidinediones, and glitazones. The reaction involves the formation of a bis(trichlorosilyl) nucleophilic intermediate from cyclic carboxyimides, which then reacts with aldehydes through a cyclic transition state, leading to highly enantioselective aldol reactions. Additionally, N-unprotected carboxyimides can be chemoselectively activated, even in the presence of N-alkylated carboxyimides, for stereoselective and chemoselective aldol reactions via in situ silicon tetrachloride activation. The functionalized cyclic carboxyimides can be easily derivatized to various chiral building blocks without the need for unnecessary protection/deprotection steps.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Review
Chemistry, Organic
Zorana Ferjancic, Radomir N. Saicic
Summary: The combination of organocatalytic aldol reaction and reductive amination allows for rapid, stereoselective synthesis of N-heterocycles, which is of great significance for the synthesis of iminosugars and other polyhydroxylated alkaloids.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Review
Chemistry, Organic
Tania Xavier, Sylvie Condon, Christophe Pichon, Erwan Le Gall, Marc Presset
Summary: Substituted malonic acid half-oxyesters (SMAHOs) are an original family of malonic acid derivatives that can serve as pro-nucleophiles for greener methodologies through decarboxylative processes. The presence of a substituent on the malonic position offers opportunities for structural diversification. These reagents are well-suited for the development of organocatalyzed processes, and have recently been used for olefination and addition reactions to synthesize elaborated structures under mild conditions.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Aolin Cheng, Liangliang Zhang, Qinghai Zhou, Tao Liu, Jing Cao, Guoqing Zhao, Kun Zhang, Guanshui Song, Baoguo Zhao
Summary: The direct asymmetric aldol reaction of glycinates has been achieved by using chiral N-methyl pyridoxal as the catalyst, leading to high yields of chiral beta-trifluoromethyl-beta-hydroxy-alpha-amino-acid esters with excellent stereoselectivity and enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Ciril Jimeno
Summary: The research was inspired by the binding and stabilizing effect of arginine residues in certain aldolases, leading to the development of a new family of amino acylguanidine organocatalysts. Screening and optimization identified the threonine derivative as the most suitable catalyst for asymmetric aldol addition, while the proline derivative yielded the anti diastereomer. MMFF models indicated the presence of an extensive hydrogen bonding network between the acylguanidinium group and the reaction intermediates.
Article
Chemistry, Multidisciplinary
Camille Banoun, Flavien Bourdreux, Guillaume Dagousset
Summary: We describe a versatile and highly selective method for gamma-functionalization under visible light. This gentle radical approach expands the application range to unbiased enals and allows the introduction of various alkoxy, amino, and alkyl functionalities at the gamma position with complete regioselectivity.
CHEMICAL COMMUNICATIONS
(2023)
Article
Polymer Science
Yanping Li, Ke Pan, Yougen Chen
Summary: A new type of degradable poly(beta-trimethylsilyloxy ester) was synthesized by the organocatalyzed Mukaiyama aldol polyaddition. These polyesters showed degradation behavior in the presence of nucleophiles, and the degradation mechanism was influenced by the nature of the catalyst used.
MACROMOLECULAR RAPID COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Mariia Babkova, Rene Wilhelm
Summary: In this study, a series of new multifunctional organocatalysts were prepared and evaluated for the asymmetric aldol reaction of acetone and aromatic aldehydes. Several of the catalysts exhibited high catalytic activity and selectivity. The combination of camphor-based moiety and proline-based unit was found to be crucial for the performance of the catalysts.
Article
Chemistry, Multidisciplinary
Pei Wang, Yang Zhang, Hong Yang, Guo-Rong Ma, Jin-Bao Wang, Wen Yang, Zhi-Hong Du, Chao-Shan Da
Summary: An efficient strategy has been developed for the construction of (R)-3-alkyl-3-hydroxyindolin-2-one and (S)-5-trifluoromethyl-4-hydroxy-4-arylpentan-2-one derivatives catalyzed by the beta-turn tetrapeptide catalyst, yielding high product yields with good enantioselectivity.
Review
Chemistry, Organic
Maria A. Theodoropoulou, Nikolaos F. Nikitas, Christoforos G. Kokotos
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2020)
Article
Chemistry, Organic
Nikoleta Spiliopoulou, Constantinos T. Constantinou, Ierasia Triandafillidi, Christoforos G. Kokotos
SYNTHESIS-STUTTGART
(2020)
Article
Chemistry, Organic
Nikolaos F. Nikitas, Errika Voutyritsa, Petros L. Gkizis, Christoforos G. Kokotos
Summary: A simple, photochemical, and metal-free protocol for the atom transfer radical addition (ATRA) of bromotrichloromethane onto various alkenes is described, with phenylglyoxylic acid proving to be the most suitable photoinitiator. This protocol can be expanded into a wide substrate scope of aliphatic olefins with various functional groups, leading to good to excellent yields of the corresponding products.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Nikolaos F. Nikitas, Maria A. Theodoropoulou, Christoforos G. Kokotos
Summary: This study presents a new photochemical methodology for the reaction between N,N-dimethylanilines and N-substituted maleimides, using benzaldehyde as the photoinitiator. Various substituted N,N-dimethylanilines and N-substituted maleimides were successfully converted into corresponding adducts in moderate to high yields.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Elpida Skolia, Mary K. Apostolopoulou, Nikolaos F. Nikitas, Christoforos G. Kokotos
Summary: An efficient, green, and metal-free photochemical protocol for synthesizing benzimidazoles has been developed using 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator and CFL lamps as the light source. Good to high yields of the corresponding benzimidazoles were obtained, and mechanistic studies were conducted to determine the plausible reaction mechanism.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Nikolaos F. Nikitas, Mary K. Apostolopoulou, Elpida Skolia, Anna Tsoukaki, Christoforos G. Kokotos
Summary: A cost-effective and straightforward photochemical method has been developed for the activation of aromatic aldehydes, leading to the conversion into various products including a drug for depression and social anxiety. Detailed mechanistic studies have been conducted to determine a plausible mechanism for the reaction.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Medicinal
Charikleia S. Batsika, Christiana Mantzourani, Dimitrios Gkikas, Maroula G. Kokotou, Olga G. Mountanea, Christoforos G. Kokotos, Panagiotis K. Politis, George Kokotos
Summary: The discovery of saturated oxo fatty acids (SOFAs) has shown potential in inhibiting the growth of human lung carcinoma cells. Particularly, 6OSA and 7OSA exhibited the most significant inhibitory effect on cell growth, affecting crucial regulators of cell growth and proliferation.
JOURNAL OF MEDICINAL CHEMISTRY
(2021)
Article
Chemistry, Applied
Zdravko Dzambaski, Aleksandra M. Bondzic, Ierasia Triandafillidi, Christoforos G. Kokotos, Bojan P. Bondzic
Summary: Organic single-electron oxidant in the presence of diarylprolinol silylether type catalyst can transform electron-rich enamines to iminium ions, which then participate in a subsequent Michael-initiated ring-closure reaction with in situ nucleophile to yield stereodefined cyclopropanes from saturated aldehydes. This one-pot transformation exemplifies the use of saturated aldehydes in coupled processes, providing high yields and selectivities.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Nikoleta Spiliopoulou, Petros L. Gkizis, Ierasia Triandafillidi, Nikolaos F. Nikitas, Charikleia S. Batsika, Aikaterini Bisticha, Christoforos G. Kokotos
Summary: In this paper, we restudied the mechanism of action of phenylglyoxylic acid (PhCOCOOH) in photochemical reactions and proposed a unified mechanism. Additionally, we compared its action as a photoinitiator with known and commercially available photoinitiators.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Ierasia Triandafillidi, Nikolaos F. Nikitas, Petros L. Gkizis, Nikoleta Spiliopoulou, Christoforos G. Kokotos
Summary: This paper investigates the photocatalytic reaction between alkynes and maleimides, comparing the reactivity differences between N-alkyl and N-aryl maleimides. The results show that using hexafluoroisopropanol or trifluoroacetic acid as solvents can achieve high yields in the reaction.
Article
Biochemistry & Molecular Biology
Giorgos S. Koutoulogenis, Nikoleta Spiliopoulou, Christoforos G. Kokotos
Summary: A novel, mild, metal-free procedure for the C-H acetalization of O-heterocycles via visible light activation using phenylglyoxylic acid as the photoinitiator is presented. Biomass-derived O-heterocycles such as THF can be used, and a variety of alcohols with different functionalities can be successfully employed to afford the desired acetals in high yields. Convenient acidic deprotection was also carried out.
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
(2022)
Review
Chemistry, Multidisciplinary
Elpida Skolia, Petros L. Gkizis, Chistoforos G. Kokotos
Summary: This review summarizes the photochemical protocols for the oxidation of sulfides to sulfoxides using oxygen or air as the oxidant. The review includes a historical overview, key mechanistic studies and proposed mechanisms, as well as categorizing different catalytic systems in the literature.
Article
Chemistry, Multidisciplinary
Ierasia Triandafillidi, Maroula G. Kokotou, Dominik Lotter, Christof Sparr, Christoforos G. Kokotos
Summary: The organocatalytic epoxidation of unactivated alkenes using aqueous hydrogen peroxide provides essential products and intermediates in a sustainable manner. A specific atropisomeric two-axis aldehyde was identified for high-yielding epoxidations of cyclic and acyclic alkenes, resulting in high catalytic efficiencies due to the proximity of the aldehyde and backbone residues. Mechanistic studies suggest a non-radical alkene oxidation by an aldehyde-derived dioxirane intermediate generated from hydrogen peroxide through the Payne and Criegee intermediates.
Review
Chemistry, Organic
Nikolaos F. Nikitas, Petros L. Gkizis, Christoforos G. Kokotos
Summary: Photoorganocatalysis is recognized as an important aspect of photochemistry and catalysis in organic chemistry, with aromatic ketones playing a significant role. Thioxanthone (TX) stands out for its unique properties in photochemistry, with high triplet energy and long triplet lifetime, making it effective in merger reactions with metal complexes. This review discusses the photophysical properties of TX and its applications in various photochemical reactions, particularly in polymerization and organic transformations.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Nikoleta Spiliopoulou, Christoforos G. Kokotos
Summary: A new photochemical approach for the synthesis of symmetrical and non-symmetrical disulfides is described, utilizing mild, inexpensive and green conditions. The method involves the use of phenylglyoxylic acid as the photoinitiator, household bulbs as the light source, and a simple inorganic salt as the additive, resulting in excellent yields of the products.
Article
Chemistry, Organic
Fuying Zhu, Yamei Lin
Summary: In this study, a low-metal iron-supported catalyst (Fe20/NC-Mg) was reported for the efficient synthesis of quinoxaline compounds, using water as a solvent and without additional bases. The synergistic effect of FeNx site and Mg (OH)2 nanorods in the catalyst played a key role in achieving high yields (82-91%) in 16 examples. The gram-level synthesis and reusability of the catalysts after four cycles demonstrated its industrial application potential.
Article
Chemistry, Organic
Mikhail Kozlov, Alexey Tyurin, Andrey Dmitrenok, Vyacheslav Rusak, Aleksander Fedorov, Igor Zavarzin, Yulia Volkova
Summary: This study presents a novel and practical synthesis method for phosphorus-substituted 1,3,4-thiadiazolines using phosphorylthioformic acid hydrazides and ketones. The protocol demonstrates operational simplicity, availability of reagents, and tolerance towards different functional groups.
Article
Chemistry, Organic
Jisna Jose, Thomas Mathew
Summary: 2-Cyclopentenone and its derivatives are highly esteemed synthetic intermediates with exceptional utility in organic synthesis. They are favored structural motifs in numerous pharmaceutical drugs and natural products, highlighting their significance. The review discusses the various methods used to synthesize cyclopentenones from 2016 to 2023.
