Article
Chemistry, Multidisciplinary
Min Zhu, Hua-Jie Jiang, Illia Sharanov, Elisabeth Irran, Martin Oestreich
Summary: A desymmetrizing silylation of aromatic diols is achieved by using List's counteranion directed silylation technique for asymmetric silyl ether formation of phenol derivatives. The enantioselective discrimination of achiral 1,1'-biaryl-2,6-diols is enabled by a silylium-ion-like silicon electrophile generated from an allylic silane paired with an imidodiphosphorimidate (IDPi). The enantioselectivity of the desymmetrization is further improved by a downstream kinetic resolution, converting the monosilylated minor enantiomer into the corresponding bissilylated diol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Kodai Wakafuji, Satsuki Iwasa, Kina N. Ouchida, Hyemin Cho, Hirotsugu Dohi, Eiji Yamamoto, Takashi Kamachi, Makoto Tokunaga
Summary: This study demonstrated the phase-transfer catalytic asymmetric alcoholysis of azlactones via dynamic kinetic resolution, yielding alpha-chiral amino acid esters with high yield and selectivity. Detailed computational studies revealed a transition state model involving water or alcohol molecules activating the substrate and stabilizing the transition state through various weak interactions, leading to the major enantiomer.
Review
Chemistry, Multidisciplinary
Yi Zhang, Hui Cai, Xiuhai Gan, Zhichao Jin
Summary: This paper provides a systematic review of N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions, dynamic kinetic resolutions, and desymmetrization reactions. The content is organized based on the activation modes involved in these transformations. Future advances in this highly active research field are also discussed from the authors' perspectives.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Biki Ghosh, Reena Balhara, Garima Jindal, Santanu Mukherjee
Summary: The first catalytic enantioselective Fischer indolization of prochiral diketones containing enantiotopic carbonyl groups is developed through dynamic kinetic resolution. Catalyzed by a combination of a spirocyclic chiral phosphoric acid and ZnCl2, this approach efficiently synthesizes cyclopenta[b]indole derivatives with an all-carbon quaternary stereocenter in good to excellent enantioselectivities.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Chemistry, Organic
Helene Pellissier
Summary: Organocatalytic dynamic kinetic resolution (DKR) has emerged as a promising field in the past two decades, allowing efficient separation of chiral compounds. This review aims to provide an update on organocatalytic DKRs since 2016.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Sarah A. Cronin, Stephen J. Connon
Summary: This study introduces a novel approach to catalytic, alcoholytic kinetic resolution of oxazinones using a stereochemically dense cinchona alkaloid-based catalyst. The catalyst enables highly enantiodiscriminatory ring-opening of oxazinones equipped with electrophilic aryl units, leading to the generation of orthogonally protected beta-amino acids for the first time.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Xi Yuan, Jian Wang
Summary: A highly efficient enantioselective synthesis of heterobiaryl N-oxides has been achieved, and their potential as chiral ligands in asymmetric catalysis has been demonstrated.
SCIENCE CHINA-CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Bang-An Zhou, Xue-Ning Li, Chun-Lin Zhang, Zhi-Xiang Wang, Song Ye
Summary: The N-heterocyclic carbene-catalyzed enantioselective synthesis of axially chiral diaryl ethers via desymmetrization of prochiral 2-aryloxyisophthalaldehydes has been presented. This method exhibits mild reaction conditions, broad substrate scope, and excellent enantioselectivity. The utility of this methodology has been demonstrated through late-stage functionalization and various enantioretentive transformations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Sanjiv O. Tomer, Hemant P. Soni
Summary: In this study, the molecular structure of quinidine was modified and a chiral hemiester catalyst with high enantioselectivity and yield was successfully synthesized.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Harrison M. Snodgrass, Dibyendu Mondal, Jared C. Lewis
Summary: In this study, a variant of the flavin-dependent halogenase RebH was engineered to catalyze site- and atroposelective halogenation reactions of 3-aryl-4(3H)-quinazolinones. The directed evolution process used a combination of mutagenesis, substrate walking, and screening methods to improve the conversion and selectivity of the enzyme. The resulting variant showed high activity and selectivity on multiple substrates, and computational modeling was used to understand the effects of key mutations on substrate binding. This study demonstrates the potential of flavin-dependent halogenases for atroposelective catalysis and highlights the versatility of RebH in accepting structurally diverse substrates for enantioselective synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Ayumi Imayoshi, Bhatraju Vasantha Lakshmi, Yoshihiro Ueda, Tomoyuki Yoshimura, Aki Matayoshi, Takumi Furuta, Takeo Kawabata
Summary: Since the discovery of mechanically planar chiral rotaxanes and topologically chiral catenanes, their asymmetric synthesis has been a long-standing challenge. Here, the authors report enantioselective preparation of mechanically planar chiral rotaxanes with up to 99.9% ee in 29% yield.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Song Sun, Zhaobin Wang, Shijia Li, Cong Zhou, Lijuan Song, Hai Huang, Jianwei Sun
Summary: This study presents the first organocatalytic kinetic resolution of unactivated aziridines using sulfur nucleophiles, achieving excellent enantioselectivity. A chiral phosphoric acid was identified as an efficient catalyst for intermolecular ring opening under mild conditions, providing highly enantioenriched beta-amino thioethers and aziridines as useful synthetic building blocks.
Review
Chemistry, Organic
Wei Liu, Xiaoyu Yang
Summary: Chiral phosphoric acids have been recognized as one of the most powerful chiral organocatalysts and have been extensively applied in kinetic resolution, dynamic kinetic resolution and desymmetrization reactions, leading to significant developments in these areas since 2016.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Eddy Jimenez, Margarita Cantu-Reyes, Miguel Flores-Ramos, Carlos A. Roman-Chavarria, Howard Diaz-Salazar, Marcos Hernandez-Rodriguez
Summary: The asymmetric ring opening of azlactones via dynamic kinetic resolution (DKR) was studied by comparing different thioureas. The catalysts with additional chiral centers outperformed Takemoto's thiourea. The difference in yield and selectivity between the fluorinated and non-fluorinated catalysts was minimal. The analysis of calculated transition states showed that the hydrogen bond (HB) between the NH linked to the 1-arylethyl and the negatively charged oxygen in the benzyloxy ion was the longest in the HB network, indicating that the substituents and the HB donor ability of the chiral fragment attached to the thiourea were not important in the reaction.
Article
Chemistry, Physical
Min Zhu, Martin Oestreich
Summary: A group-selective monosilylation of silanediols using List's counteranion-directed silylation methodology is described. The enantioselectivity is achieved by generating a silylium-ion-like silicon electrophile from an allylic silane paired with an imidodiphosphorimidate (IDPi), enabling discrimination of the two hydroxy groups attached to the prochiral silicon atom. Furthermore, the enantioselectivity is improved by a subsequent kinetic resolution, resulting in silicon-stereogenic disiloxanes with high enantiocontrol.
Article
Chemistry, Multidisciplinary
Aaron Gutierrez Collar, Cristina Trujillo, Bruce Lockett-Walters, Brendan Twamley, Stephen J. Connon
CHEMISTRY-A EUROPEAN JOURNAL
(2019)
Article
Chemistry, Multidisciplinary
Aaron Gutierrez Collar, Cristina Trujillo, Stephen J. Connon
CHEMISTRY-A EUROPEAN JOURNAL
(2019)
Article
Chemistry, Physical
Cristina Trujillo, Mili Litvajova, Sarah A. Cronin, Ryan Craig, Stephen J. Connon
Article
Chemistry, Multidisciplinary
Simon N. Smith, Ryan Craig, Stephen J. Connon
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Simon P. Curran, Brendan J. Fallon, Stephen J. Connon
Article
Biochemistry & Molecular Biology
Claire Fergus, Mashael Al-Qasem, Michelle Cotter, Ciara M. McDonnell, Emiliano Sorrentino, Franciane Chevot, Karsten Hokamp, Mathias O. Senge, John M. Southern, Stephen J. Connon, Vincent P. Kelly
Summary: Base modification can occur throughout a transfer RNA molecule, with a particular emphasis on position 34 of the anticodon loop. Human enzymes can recognize a wide range of artificial derivatives for transfer RNA incorporation, while displaying strict specificity for decoding certain codons. Exploiting the queuosine incorporation pathway shows broad potential for intentionally engineering chemical diversity into transfer RNA anticodons.
NUCLEIC ACIDS RESEARCH
(2021)
Article
Chemistry, Organic
Mili Litvajova, Emiliano Sorrentino, Brendan Twamley, Stephen J. Connon
Summary: This study demonstrates the application of N-protected oxindole derivatives with unprecedented malleability in enantioselective phase-transfer-catalysed alkylations. By optimizing the structure of the catalyst, high levels of enantioselectivity were achieved. It was found that urea-based catalysts outperformed squaramide derivatives, and that installing a chlorine atom in the quinoline moiety of the catalyst improved reaction selectivity.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Simon N. Smith, Stephen J. Connon
Summary: The ring contraction-lactamisation of anhydrides with trimethylsilylazide in the presence of an amine catalyst has been studied. It is possible to generate 5,- 6- and 8-membered ring lactams from cyclic anhydrides under controlled conditions, with a simple operation procedure. Succinic anhydrides can be used to produce N-carboxyanhydrides for polymer chemistry and as beta-peptide precursors.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Cristina Trujillo, Sarah A. Cronin, Stephen J. Connon
Summary: A complete computational study was conducted to rationalize a new organocatalytic approach for the kinetic resolution of 4-substituted oxazinones, resulting in highly enantioenriched beta-amino acids. The study also investigated the alcoholytic kinetic resolution of a 7-memebered ring analogue for the first time, generating enantioenriched gamma-amino acids.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Medicinal
Ciara M. McDonnell, Magda Ghanim, J. Mike Southern, Vincent P. Kelly, Stephen J. Connon
Summary: This study investigates the impact of modified beta-lysines on the growth rates of eubacterial cells. The results indicate that the observed effects are due to the post translational modification of Elongation Factor P (EFP) catalyzed by PoxA. The promiscuity of PoxA allows for examination of a wide range of exogenous beta-lysines.
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Organic
Sarah A. Cronin, Stephen J. Connon
Summary: This study introduces a novel approach to catalytic, alcoholytic kinetic resolution of oxazinones using a stereochemically dense cinchona alkaloid-based catalyst. The catalyst enables highly enantiodiscriminatory ring-opening of oxazinones equipped with electrophilic aryl units, leading to the generation of orthogonally protected beta-amino acids for the first time.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Eoghan G. Delany, Stephen J. Connon
Summary: The enantioselective intermolecular crossed-benzoin condensation mediated by novel chiral N-heterocyclic carbenes derived from pyroglutamic acid has been investigated. Increasing both the steric requirement and the electron-withdrawing characteristics of the N-aryl ring led to more chemoselective, efficient and enantioselective chemistry. Subsequent protocol optimization involving o-substituted benzaldehyde as one reacting partner allowed a range of crossed-benzoins to be synthesized in moderate-good yields with moderate to excellent enantioselectivity.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Mashael A. Alqasem, Claire Fergus, J. Mike Southern, Stephen J. Connon, Vincent P. Kelly
CHEMICAL COMMUNICATIONS
(2020)
Article
Chemistry, Multidisciplinary
Amy C. Maguire, Vikas Kumar, Stephen J. Connon
CHEMICAL COMMUNICATIONS
(2019)
Article
Chemistry, Multidisciplinary
Bruce Lockett-Walters, Cristina Trujillo, Brendan Twamley, Stephen Connon
CHEMICAL COMMUNICATIONS
(2019)
