Article
Chemistry, Organic
Stefan Malatinec, Eva Bednarova, Hiroki Tanaka, Martin Kotora
Summary: This study presents a catalytic and highly enantioselective ring-opening reaction of epoxides, utilizing newly designed chiral bipyridine ligands. A Sc-complex with a newly developed bipyridine ligand demonstrated high reactivity and stereocontrol in the desymmetrization of meso-epoxides with various alcohols, achieving enantioenriched 1,2-alkoxyalcohols with high e.r. values. Additionally, attempted ring-opening of meso-epoxides with anilines showed lower enantioselectivity, dependent on the electronic effect of substituents on the aromatic ring.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Simona Zeimyte, Sigitas Stoncius
Summary: The newly synthesized chiral Lewis basic bipyridine N,N'-dioxides exhibited good catalytic activity in asymmetric synthesis reactions, providing high yields of target products, but the enantioselectivity needs improvement.
Article
Chemistry, Multidisciplinary
Soumen Barik, Sayan Shee, Soumik Das, Rajesh G. Gonnade, Garima Jindal, Subrata Mukherjee, Akkattu T. Biju
Summary: This study describes the atroposelective synthesis of N-aryl succinimides with axially chiral C-N bonds catalyzed by N-heterocyclic carbenes, achieving good yields and ee values. Preliminary investigations were also conducted on the rotation barrier for the C-N bond, temperature dependence, and detailed DFT studies on the mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Kazutaka Sanada, Aoi Washio, Hiroki Ishikawa, Yasushi Yoshida, Takashi Mino, Masami Sakamoto
Summary: This article presents a method for chiral symmetry breaking of monoacylated meso diols and demonstrates its effectiveness through experiments and structural analysis. The results show that Viedma ripening can efficiently produce enantiomer crystals, achieving asymmetric expression and amplification of sugar derivatives without an external chemical chiral source. Additionally, the method is successfully applied to asymmetric desymmetrization of acyclic meso-1,2-diols.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Masaru Kondo, Kento Nakamura, Chandu G. Krishnan, Hiroaki Sasai, Shinobu Takizawa
Summary: This study presents recent advances in photoswitchable chiral organocatalysts and their applications in the photomodulation of enantioselective reactions. Under appropriate light irradiation, the E/Z-photoisomerization of the photoresponsive units on the catalysts controls the catalytic activity and/or selectivity of the reactions. The study also elucidates the design, synthesis, and catalytic application of azobenzene BINOL-based photoswitchable chiral phase-transfer catalysts. This account provides insights into the appropriate design of a photoswitchable chiral organocatalyst for achieving good enantioselectivity and photocontrol.
Article
Chemistry, Organic
Changgong Xu, Phillip Nader, Jonathan Xavier, Norito Takenaka
Summary: This study presents the first catalytic asymmetric allenylation of acylhydrazones using (M)-helicene-derived 2,2'-bipyridine N-monoxide as a catalyst, which exhibits excellent regioselectivity and moderate-to-good enantioselectivity.
Article
Chemistry, Physical
Qingqing Luo, Zhou Tian, Jie Tang, Jie Wang, Yin Tian, Cheng Peng, Gu Zhan, Bo Han
Summary: The study focuses on the design of bifunctional 4-pyrrolidinopyridines as Lewis base catalysts, which exhibited excellent efficiency and stereoselectivity in asymmetric cycloaddition reactions. The research provides strong support for the construction of chiral spiropyrazolone derivatives.
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
Polymer Science
Peng Du, Yao Li, Xiao-Bing Lu
Summary: Asymmetric organocatalysis has been widely used in the synthesis of small chiral molecules, but its application in the synthesis of enantioenriched polymers is limited. This study presents a metal-free asymmetric catalytic copolymerization of meso-epoxides with CO2 using chiral organoboron-based bifunctional and binary catalysts. Although the enantioselectivities of the resulting copolymers are lower than those of metal-based catalyst systems, it is the first example of organocatalyzed synthesis of enantioenriched and perfectly alternating copolymers via asymmetric polymerization.
Article
Polymer Science
Peng Du, Yao Li, Xiao-Bing Lu
Summary: This article presents a metal-free asymmetric catalytic copolymerization method for synthesizing enantioenriched and perfectly alternating copolymers. By using a chiral organoboron and a binary catalyst system, polycarbonates with controlled molecular weights and narrow dispersities can be efficiently synthesized at low catalyst loading over a broad temperature range.
Article
Chemistry, Multidisciplinary
Zhi-Han Chen, Tian-Zhen Li, Ning-Yi Wang, Xiao-Fang Ma, Shao-Fei Ni, Yu-Chen Zhang, Feng Shi
Summary: This study introduces a novel strategy for the enantioselective synthesis of axially chiral N,N'-bisindoles using chiral phosphoric acid-catalyzed formal cycloadditions. The synthesized compounds showed excellent yields and enantioselectivities, and exhibited cytotoxicity towards cancer cells. Moreover, they were also transformed into axially chiral phosphine ligands with high catalytic activity.
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, Physical
Yoshinori Hashimoto, Shingo Harada, Ryosuke Kato, Kotaro Ikeda, Jannis Nonnhoff, Harald Groeger, Tetsuhiro Nemoto
Summary: This study reported a catalytic approach for the formal synthesis of more than 20 types of sarpagine/macroline alkaloids, with two key steps being the amide insertion reaction using cheap copper and biocatalytic asymmetric desymmetrization.
Article
Chemistry, Organic
Feng Jiang, Tengfei Meng, Ying Zhou, Zhenying Xiong, Yupei Zhao, Wengang Guo
Summary: We report an enantio- and diastereodivergent synthesis of enantioenriched fluorenes with broad substrate scope and high enantioselectivity (up to 99% ee) under low catalyst loading (0.1 mol %). The success of this method lies in the pseudo-diastereodivergent desymmetrization of stereoisomers of meso-epoxides enabled by the same organocatalyst. Furthermore, some of the chiral fluorenes obtained exhibit high fluorescence quantum yields (up to 76.6%), as evidenced by photophysical properties studies.
Article
Chemistry, Multidisciplinary
Tsubasa Inokuma, Kentaro Hashimoto, Tatsuya Fujiwara, Chunzhao Sun, Satoru Kuwano, Ken-ichi Yamada
Summary: The remote electronic effect of a chiral aminoindanol-derived N-heterocyclic carbene catalyst on an asymmetric benzoin reaction was investigated. The catalyst containing remote electron-withdrawing substituents increased the enantioselectivity of the reaction, albeit at the expense of the reaction rate. DFT calculations provided a rationale for the enhanced enantioselectivity.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Jayaraman Selvakumar, Selvaraj Mangalaraj, Kamsali Murali Mohan Achari, Krishna Mukund, Chinnasamy Ramaraj Ramanathan
SYNTHESIS-STUTTGART
(2017)
Article
Chemistry, Medicinal
Anand H. Shinde, Someshwar Nagamalla, Shyam Sathyamoorthi
MEDICINAL CHEMISTRY RESEARCH
(2020)
Article
Chemistry, Medicinal
Someshwar Nagamalla, David K. Johnson, Shyam Sathyamoorthi
Summary: The study describes an approach to analogs of antibiotic Bactobolin A through sulfamate-tethered aza-Wacker cyclization reactions. Docking studies reveal interactions of C4 epimer and C4/C6 diastereomer with different residues of 23S rRNA, suggesting their potential as valuable tool compounds for fundamental studies of bacterial translational machinery.
MEDICINAL CHEMISTRY RESEARCH
(2021)
Article
Chemistry, Organic
Someshwar Nagamalla, Joel T. Mague, Shyam Sathyamoorthi
Summary: This study presents a new ring-opening reaction of epoxides catalyzed by pendant silanols. Different types of silanol epoxides derived from various allylic alcohols were compatible and yielded products with either endo- or exo-ring opening. An unusual rearrangement to tetrahydrofuran products was observed with one type of silanol epoxide derived from 4-alkenyl silanols. The utility of this methodology was demonstrated in a short preparation of protected D-arabitol.
Article
Chemistry, Organic
Someshwar Nagamalla, Debobrata Paul, Joel T. Mague, Shyam Sathyamoorthi
Summary: We present a unique strategy for the synthesis of vicinal amino alcohols through ring opening of aziridines with pendant silanols, which is compatible with a range of substrates. This method requires mild activation of the aziridine and tolerates various N-substituents. It has been successfully applied in the facile preparation of natural products and analogues.
Article
Chemistry, Organic
Someshwar Nagamalla, Joel T. Mague, Shyam Sathyamoorthi
Summary: This progress report presents the research towards Bactobolin A and C4-epi-Bactobolin A. Key intermediates were synthesized through specific chemical reactions, which can be further elaborated into the desired compounds.
Article
Chemistry, Organic
Someshwar Nagamalla, Joel T. Mague, Shyam Sathyamoorthi
Summary: This paper presents the development of a novel method for the ring opening of epoxides using pendant sulfamates and sulfamides. These reactions, catalyzed by a base, proceed under mild conditions and exhibit excellent diastereoselectivity and regiocontrol in the formation of oxathiazinanes and cyclic sulfamides. The scalability of these reactions is demonstrated, and the resulting products can serve as valuable intermediates for further ring-opening reactions.
Article
Chemistry, Organic
Someshwar Nagamalla, Ranjeet A. Dhokale, Frederick J. Seidl, Joel T. Mague, Shyam Sathyamoorthi
Summary: The first examples of rearrangement reactions of allylic silanol substrates into linear ketone and 5-membered cyclic silanediol organomercurial products are presented in this study. The reactions are mediated by Hg(OTf)(2) and show differences in the use of base, solvent, and temperature. Mechanistic studies suggest that these products result from a series of cascading transformations in one pot, with a DFT analysis providing insights into the rearrangement process.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Anita Sahani, Ramana Sreenivasa Rao, Adithya Vadakkayil, Murugesan Santhosh, Mahalingam Mummoorthi, Muthupandi Karthick, Chinnasamy Ramaraj Ramanathan
Summary: Niobium pentoxide is an efficient catalyst that can facilitate the three-component reaction between aldehydes, amines, and triethyl phosphite to generate alpha-amino phosphonate under solvent-free conditions at room temperature. The catalyst is recyclable through simple filtration for repeated use in this transformation.
JOURNAL OF CHEMICAL SCIENCES
(2021)
Article
Chemistry, Organic
Muthupandi Karthick, Edwin Konikkara Abi, Nagamalla Someshwar, Savarimuthu Philip Anthony, Chinnasamy Ramaraj Ramanathan
ORGANIC & BIOMOLECULAR CHEMISTRY
(2020)
Review
Chemistry, Multidisciplinary
Annu Anna Thomas, Someshwar Nagamalla, Shyam Sathyamoorthi
Article
Chemistry, Organic
Kesa Venkatanna, Santhakumar Yeswanth Kumar, Muthupandi Karthick, Ramanathan Padmanaban, Chinnasamy Ramaraj Ramanathan
ORGANIC & BIOMOLECULAR CHEMISTRY
(2019)
Article
Chemistry, Multidisciplinary
Kamsali Murali Mohan Achari, Muthupandi Karthick, Chinnasamy Ramaraj Ramanathan
JOURNAL OF CHEMICAL SCIENCES
(2017)
Article
Chemistry, Organic
Ramana Sreenivasa Rao, Chinnasamy Ramaraj Ramanathan
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2017)
