Article
Chemistry, Organic
Jie Zheng, Meng-Yu Rong, Fang-Fang Feng, Fa-Guang Zhang, Chi Wai Cheung, Jun-An Ma
Summary: In this study, the organocatalytic asymmetric aza-Friedel-Crafts-type reaction of indol-3-ones with 1- and 2-naphthols was performed using spirocyclic chiral phosphoric acids and quinine-incorporated squaramides as the organocatalysts. Two classes of structurally distinct chiral compounds, namely 2-(hydroxylnaphthyl)-indolin-3-ones and tetrahydrofuroindoles, were formed. These quaternary centre-containing indoline derivatives may have applications in the synthesis of biologically active molecules.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yuki Saito, Shu Kobayashi
Summary: The article discusses the application of chiral heterogeneous Sc catalysts in continuous-flow reactions, achieving efficient synthesis of compounds through noncovalent interactions and the crucial role of heteropoly acid.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Hailong Zhang, Romain Carlino, Regis Guillot, Richard Gil, Sophie Bezzenine, Jerome Hannedouche
Summary: A new method for efficient cyclization of δ/ε-alkenoic acids and N-protected δ-alkenamides using easily accessible Lewis acid scandium(III) triflate under thermal and microwave conditions is reported for the first time. The selectivity of the reaction depends on the substitution patterns of the backbone chain and alkene moiety, resulting in exclusive formation of γ/ε-lactones via O-selective cyclization or Friedel-Crafts-type products via C-selective cyclization. Uncommon O-selective cyclization occurred preferentially or exclusively with N-protected δ-alkenamides, confirmed by single crystal X-ray crystallography.
Article
Chemistry, Multidisciplinary
Rajasekar Reddy Annapureddy, Finn Burg, Johannes Gramueller, Tino P. Golub, Christian Merten, Stefan M. Huber, Thorsten Bach
Summary: An enantioselective sulfimidation of 3-thiosubstituted 2-quinolones and 2-pyridones was achieved with a stoichiometric nitrene source and a silver-based catalyst system, producing 21 chiral sulfimides in high yields and with significant enantiomeric excess. The reaction demonstrates high site-selectivity and potential for kinetic resolution of chiral sulfoxides. Mechanistic evidence supports the involvement of a heteroleptic silver complex in the reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Ryoya Tajima, Takaaki Saito, Takayoshi Arai
Summary: The conventional acid-catalyzed aza-Friedel-Crafts reaction of phenols with imines typically shows ortho-selectivity. However, a chiral bis(imidazolidine) pyridine (PyBidine)-Ni(OAc)(2) catalyst can switch the regioselectivity to para-selectivity. This switch is facilitated by the bulky PyBidine-Ni(OAc)(2) catalyst with a Ph2CHCH2 substituent, resulting in highly para-selective aza-Friedel-Crafts reactions (up to 99:1 para/ortho selectivity).
Review
Chemistry, Multidisciplinary
Jia-Jun Jiang, Man-Kin Wong
Summary: This review summarizes the rapid development of asymmetric gold catalysis in the past ten years, focusing on newly developed gold-catalyzed enantioselective organic transformations and recent progress in ligand design since 2016, organized according to different types of chiral ligands for asymmetric gold(I) and gold(III) catalysis.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Article
Chemistry, Organic
Sk Md Samim Akhtar, Sukanta Bar, Saumen Hajra
Summary: A proficient stereoselective aminoarylation reaction of N-cinnamylanilines was developed based on a two-step protocol involving catalytic enantioselective aziridination and subsequent 6-endo-tet Friedel-Crafts cyclization. The reaction showed excellent diastereo- and enantioselectivity in the synthesis of trans-3-amino-4-aryltetrahydroquinolines, with the potential for concise synthesis of bioactive compounds.
Article
Chemistry, Organic
Amjad Ali, Raveena Jajoria, Harish K. Harit, Ravi P. Singh
Summary: In this study, the addition of alpha-ketoamide top-quinone methide initiated by dialkylphosphite in the presence of organic base DBU was explored. The coupling of dialkylphosphites to alpha-ketoamides followed[1,2]-phospha-Brook rearrangement, generating alpha-phosphonyloxy enolates that were subsequently seized by p-quinonemethides. This two-step one-pot 1,6-conjugate addition method provides effective access to a series of isatin-incorporated phosphate-bearing 1,6-adducts with high yield and selectivity.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Samim Akhtar, Saumen Hajra
Summary: A one-pot asymmetric aminoarylation reaction has been developed for the synthesis of trans-4-amino-5-aryltetrahydrobenzo[c]azepines with excellent diastereo- and enantioselectivity. The reaction proceeds through aziridination followed by intramolecular cyclicization. A chiral indenyl bis(oxazoline) ligand is found to be effective for the catalytic enantioselective version of this one-pot transformation.
Review
Chemistry, Organic
Sanjay Singh, Chinmoy K. Hazra
Summary: This review discusses recent advances and significant breakthroughs in the catalytic Friedel-Crafts alkylation of targeted arenes or heteroarenes, with a main focus on literature published between 2015 and March 2023.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Paul S. Riehl, Alistair D. Richardson, Tatsuhiro Sakamoto, Jolene P. Reid, Corinna S. Schindler
Summary: Enantiodivergence is an important concept in asymmetric catalysis, allowing access to both enantiomers of a product when only one enantiomer of the required chiral ligand is readily available. This study focuses on elucidating the origin of metal-controlled enantioselectivity reversal, showing that specific interactions between the substrate and ligand depend on the ionic radius of the metal catalyst. This research has the potential to enhance our understanding of enantiodivergent transformations and facilitate their future design.
Review
Chemistry, Multidisciplinary
Johannes Grosskopf, Thorsten Bach
Summary: Upon irradiation with a suitable chiral catalyst, racemic compounds can be converted into enantiopure compounds through a process called photochemical deracemization. This review comprehensively covers the research and current developments in this field, discussing the reactions and mechanistic details underlying the presented reaction. Photochemical deracemization offers a unique opportunity to directly obtain enantiopure compounds from racemates, and short-lived intermediates play a key role in determining the enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Louis Chassillan, Yasuhiro Yamashita, Woo-Jin Yoo, Martial Toffano, Regis Guillot, Shu Kobayashi, Giang Vo-Thanh
Summary: The enantioselective hydrophosphonylation of N-Boc imines was achieved using a new family of pseudo-symmetric guanidine-thiourea catalysts, with the catalyst being heterogenized by polymerization with styrene and applied to reactions under continuous-flow conditions. This approach provided alpha-amino phosphonates in moderate to high yields with good enantioselectivity.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Camilla Loro, Julie Oble, Francesca Foschi, Marta Papis, Egle M. Beccalli, Sabrina Giofre, Giovanni Poli, Gianluigi Broggini
Summary: Treatment of O-allyl N-tosyl carbamates with aromatic compounds in the presence of Cu(OTf)(2) or TMSOTf as promoters results in the formation of N-substituted 1-arylpropan-2-amines, 1,2-diarylpropanes, 1,1-diarylpropanes, or indanes, depending on the nature of the promoter and aryl substrates. A proposed mechanism explains the outcome of these C-H based cascades, involving initial acid promoted decarboxylative/deamidative Friedel-Crafts allylation followed by protonation of the allylated arene.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Mikhail Soldatov, Yiqi Wang, Hongzhi Liu
Summary: Phosphazene-containing porous materials and cage-like silsesquioxanes are promising for catalytic applications, with the former serving as adsorbents and basic catalysts while demonstrating high efficiency in the Knoevenagel reaction. This study highlights the potential of porous polymers based on organosiloxane compounds as basic catalysts for various reactions, opening up new perspectives in the field.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
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.
