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, Multidisciplinary
Muxing Zhou, Tatiana Gridneva, Zhenfeng Zhang, Ende He, Yangang Liu, Wanbin Zhang
Summary: This study presents an efficient route for the synthesis of chiral phthalidyl ester prodrugs using a chiral bicyclic imidazole organocatalyst and a continuous injection process. Computational studies suggest a general base catalytic mechanism different from the widely accepted nucleophilic catalytic mechanism. Analysis of key transition states reveals that CH-pi interactions, rather than previously considered cation/pi-pi interactions, play a dominant role in stereocontrol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Arianna Brandolese, Mark D. Greenhalgh, Titouan Desrues, Xueyang Liu, Shen Qu, Cyril Bressy, Andrew D. Smith
Summary: This study demonstrates the sequential acylative kinetic resolution of C-2-symmetric (+/-)-1,2-syn and (+/-)-1,3-anti-diols using a packed bed microreactor loaded with HyperBTM in flow. Each substrate class showed significant differences in relative rate constants for each KR process. Optimization of the flow system allowed for isolation of reaction products in high enantiopurity and yield.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Alexandra Bogdan, Ionut-Tudor Moraru, Pascale Auban-Senzier, Ion Grosu, Flavia Pop, Narcis Avarvari
Summary: Chiral bis(TTF) diamides were successfully synthesized from 1,2-cyclohexanediamine and the corresponding TTF acyl chlorides with good yields. The structural and chiroptical features of these new chiral TTF donors were characterized by experimental and computational methods.
Article
Chemistry, Organic
Sai-Ya Lian, Ning Li, Yin Tian, Cheng Peng, Ming-Sheng Xie, Hai-Ming Guo
Summary: This study reports a desymmetrization reaction of meso-vic-diols with a reversal of enantioselectivity catalyzed by chiral pyridine-N-oxides with l-proline as a single source of chirality. The reaction achieved a complete and controlled switch in stereoselectivity, and chiral six-membered carbocyclic uracil nucleosides were generated with excellent enantioselectivities. Through control experiments and density functional theory calculations, it was confirmed that the reaction proceeded in a bifunctional activated manner, and the distance-directed switching of enantioselectivity played a vital role.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Taeok Kim, Michael R. Bell, V. Narasimharao Thota, Todd L. Lowary
Summary: This study reports a one-pot strategy for functionalizing pyranoside 1,2-cis-diols with two different ester protecting groups. The approach selectively acylates through orthoester hydrolysis promoted by a carboxylic acid, and after removal of water and introduction of a coupling agent, the carboxylic acid is esterified with the liberated hydroxyl group. Although applied to 1,2-cis-diols on pyranoside scaffolds, this method can be applicable to similar motifs on any six-membered ring.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Stefanie Mayr, Hendrik Zipse
Summary: The relative rates of Lewis base-catalyzed acylation of aryl-substituted 1,2-diols with anhydrides of varying sizes have been determined. Depending on the anhydride reagent structure, the secondary hydroxyl group of the 1,2-diol reacts faster than the primary one. This preference is further enhanced in the second acylation step from monoesters to diesters through size and additional steric effects. The first acylation step is found to be up to 35 times faster than the second one for primary alcohols due to neighboring group effects.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Naoki Sakai, Kohei Ojima, Seiji Mori, Takeshi Oriyama
Summary: In this study, a novel chiral catalyst derived from (S)-proline was used to perform enantioselective kinetic resolution of beta-unfunctionalized primary alcohols with benzoyl chloride. Valuable chiral 2-substituted propan-1-ols were obtained with good enantioselectivities, and density functional theory calculations revealed the crucial role of noncovalent interactions, such as CH-pi interactions, in the enantioselectivity of the resolution.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Stefanie Mayr, Hendrik Zipse
Summary: A series of 24 annelated derivatives of 4-diaminopyridine (DMAP) have been synthesized and tested for their catalytic potential in the regioselective acylation of 1,2-diol substrates. The Lewis basicities of the catalysts vary due to inductive substituent effects and intramolecular stacking interactions. The selectivities of primary and secondary hydroxyl groups in catalytic acylations depend on the size and steric demand of the Lewis base and anhydride reagent.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
David Weinzierl, Mario Waser
Summary: This study presents a method for the kinetic resolution of racemic 4-hydroxy[2.2]paracyclophane through a chiral isothiourea-catalyzed acylation reaction, which allows for a synthetically useful s-factor of 20 and provides a novel entry to obtain this interesting planar chiral motive in an enantioenriched manner.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Hirofumi Nakayama, Hitomi Urai, Takeshi Oriyama
Summary: The one-pot desymmetrization of meso-1,2-diols was successfully achieved via benzoylation and subsequent silylation, leading to the formation of corresponding siloxy esters with excellent enantioselectivities. The reduction of these siloxy esters produced the corresponding beta-siloxy alcohols without any loss in enantioselectivity.
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN
(2022)
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
Theo A. Rusmore, Michael J. Behlen, Alex John, Daniel T. Glatzhofer, Kenneth M. Nicholas
Summary: In this study, chiral diimine-salen molybdenum complexes were evaluated for their potential as catalysts for oxidative kinetic resolution reactions. It was found that certain catalysts exhibited activity for the oxidation of racemic monophosphines, but with low to moderate enantioselectivities. Key structure/reactivity features of the catalysts include the presence of a p-NO2 substituent on the salen-unit increasing catalyst activity, and increasing steric bulk of the ortho-salen-substituent increasing enantioselectivity.
MOLECULAR CATALYSIS
(2021)
Article
Chemistry, Physical
Masa Sterle, Matej Hus, Matic Lozinsek, Anamarija Zega, Andrej Emanuel Cotman
Summary: Stereopure CF3-substituted syn-1,2-diols were synthesized through the reductive dynamic kinetic resolution of corresponding alkyl ketones, yielding products with >95% ee and >87:13 syn/anti ratio. This method provides a rapid access to stereopure bioactive molecules. Moreover, DFT calculations were conducted on three types of Noyori-Ikariya ruthenium catalysts to demonstrate their general ability to control stereoselectivity through hydrogen bond acceptor SO2 region and CH/pi interactions.
Article
Chemistry, Multidisciplinary
Song-Hee Yeo, Anthony Choi, Sophie Greaves, Anthony J. H. M. Meijer, Ilaria Proietti Silvestri, Iain Coldham
Summary: Highly enantiomerically enriched dihydrohydroquinolines were synthesized from quinoline in two steps. The addition of aryllithiums to quinoline with Boc protection yielded N-Boc-2-aryl-1,2-dihydroquinolines. Electrophilic trapping occurred exclusively at C-4 of the dihydroquinoline, supported by DFT studies. Kinetic resolutions with high enantioselectivities were achieved using lithium lithiation and the diamine sparteine.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Raghavan B. Sunoj
Summary: Computational chemistry has evolved into a highly interdisciplinary domain, shaping our molecular view of the world. This essay covers the historic, personal, and most modern manifestations of computational chemistry.
ISRAEL JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Organic
Manajit Das, Achyut Ranjan Gogoi, Raghavan B. Sunoj
Summary: In this paper, the molecular understanding of the role of protic solvents in organic transformations is explored using density functional and ab initio computational studies. The inclusion of explicit solvent molecules in crucial transition states has been found to improve the energetic estimates of organocatalytic and transition-metal-catalyzed reactions. An overview of the importance of an explicit-implicit solvation model is provided with the help of interesting examples.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Supratim Ghosh, Shilpa Shilpa, C. Athira, Raghavan B. Sunoj
Summary: This review highlights the importance of additives in transition metal catalyzed reactions and the establishment of molecular understanding of their role using modern computational chemistry tools. Explicit consideration of additives is crucial in identifying a more reasonable reaction mechanism of catalytic reactions.
TOPICS IN CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Soumi Tribedi, Raghavan B. Sunoj
Summary: The article discusses a novel method of chiral induction, utilizing DAPCy as a chiral catalyst to form chiral pyrrolidine derivatives through intramolecular nucleophilic addition, achieving a quantum conversion with 95% ee.
Article
Chemistry, Multidisciplinary
Md Emdadul Hoque, Ranjana Bisht, Anju Unnikrishnan, Sayan Dey, Mirja Md Mahamudul Hassan, Saikat Guria, Rama Nand Rai, Raghavan B. Sunoj, Buddhadeb Chattopadhyay
Summary: A method of para-selective borylation of aromatic amides is described using a newly designed ligand framework (defa), which shows excellent selectivity and reactivity for the para position. This method can contribute to the development of new catalytic systems and the synthesis of para-functionalized compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Manajit Das, Pooja Sharma, Raghavan B. Sunoj
Summary: The integration of machine learning into chemical catalysis has become a new paradigm for reaction development. In this study, a ML workflow was developed to predict the enantioselectivity of a class of catalytic asymmetric transformation, namely the relay Heck reaction. The ML model, built using quantum chemically derived descriptors, showed a remarkable prediction accuracy and assisted in exploring unexplored reactions.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Organic
Mirja Md Mahamudul Hassan, Biplab Mondal, Sukriti Singh, Chabush Haldar, Jagriti Chaturvedi, Ranjana Bisht, Raghavan B. Sunoj, Buddhadeb Chattopadhyay
Summary: An efficient method for ligand-free Ir-catalyzed ortho borylation of arenes has been developed, which can be applied to various important compounds and pharmaceuticals. The mechanistic pathway of the reaction has been revealed through detailed investigations. The method displays a broad substrate scope and functional group tolerance, and has achieved successful borylation of various important molecules and drugs.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Sukriti Singh, Raghavan B. Sunoj
Summary: Sustainable practices in chemical sciences can be better achieved by adopting interdisciplinary approaches that combine the advantages of machine learning in reaction discovery with small initial data. The use of a recurrent neural network-based deep generative model allows for effective learning and exploration of the chemical space, generating high-quality novel alcohol molecules.
Article
Crystallography
Sindhu Menon, Asila Salim Al-Saadi, Noura Jaber Al-Aamri, Al-Zahraa Hamood Al-Jaradi, Hajar Khalfan Al Mamari, Laila Hamed Al Haddabi, V. P. Jayachandran, C. B. Shinisha
Summary: The effect of Moringa leaves on inhibiting the crystallization of calcium oxalate, a key component of kidney stones, has been assessed and M. oleifera has shown greater inhibitory potential. Modelling methods have revealed a possible mechanism of inhibition.
JOURNAL OF CRYSTAL GROWTH
(2022)
Review
Chemistry, Multidisciplinary
Sukriti Singh, Raghavan B. Sunoj
Summary: In reaction development, higher efficiencies are desired and machine learning models can predict reaction outcomes for new choices of substrates/catalysts. However, applying machine learning to reaction discovery is challenging due to difficulties in molecular featurization, availability of quality data, and the choice of suitable models and their deployment. Feature engineering and feature learning methods can be effective in predicting reaction outcomes.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Supratim Ghosh, Avtar Changotra, David A. Petrone, Mayuko Isomura, Erick M. Carreira, Raghavan B. Sunoj
Summary: In this study, the mechanism of a chiral Ir-phosphoramidite-catalyzed asymmetric reductive deoxygenation reaction was investigated using density functional theory. It was found that Bi(OTf)3 promotes ionic and noncovalent interactions, which play a crucial role in nucleophile selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
C. Athira, A. Sreenithya, Christopher M. Hadad, Raghavan B. Sunoj
Summary: The increasing number of examples on cooperative dual catalysis involving organocatalysts and transition metal catalysts indicate their wider acceptance and utility in synthetic applications. In this study, computational investigation using density functional theory reveals the molecular mechanism and energetic features responsible for the high enantio-/diastereoselectivities and cooperativity in dual catalytic reactions.
Review
Chemistry, Physical
Shilpa Shilpa, Gargee Kashyap, Raghavan B. Sunoj
Summary: The burgeoning developments in machine learning have found notable applications in chemistry, particularly in the prediction of molecular properties and chemical reactions. This review highlights the recent advancements in ML implementations, ranging from ensemble-based models to graph neural networks. Accurate predictions in molecular property prediction, using methods such as D-MPNN, MolCLR, SMILES-BERT, and MolBERT, offer promising prospects in molecular design and drug discovery. Challenges in dealing with reaction data sets are discussed, alongside an optimistic outlook on the benefits of ML-driven workflows for various chemistry tasks.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Sandip Kumar Das, Subrata Das, Supratim Ghosh, Satyajit Roy, Monika Pareek, Brindaban Roy, Raghavan B. Sunoj, Buddhadeb Chattopadhyay
Summary: A new iron-porphyrin based catalytic system has been developed for intramolecular C-H amination of substituted tetrazolopyridines. This method exhibits high regioselectivity and excellent functional group tolerance, enabling the synthesis of three different classes of high-value N-heterocyclic scaffolds. The study also reveals the metalloradical activation mechanism of this catalytic system.
Article
Chemistry, Physical
Soumi Tribedi, Kazuo Kitaura, Takahito Nakajima, Raghavan B. Sunoj
Summary: The study delves into the origin of selectivity in asymmetric catalysis, revealing that weak noncovalent interactions can sometimes outweigh steric effects in enantiocontrolling transition states. By using the fragment molecular orbital method, the relative contributions of various attractive and repulsive interactions in the total interaction energy in enantiocontrolling transition states can be determined. This quantitative insight on intramolecular interactions may aid in the rational design of asymmetric catalysis.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
