Article
Chemistry, Organic
Paula Oroz, Claudio D. Navo, Alberto Avenoza, Jesus H. Busto, Francisco Corzana, Gonzalo Jimenez-Oses, Jesus M. Peregrina
Summary: This research describes the diastereoselective 1,4-conjugate additions of anionic and radical C-nucleophiles to a chiral bicyclic dehydroalanine (Dha). Notably, radical carbon photolysis using a metal-free photocatalyst through a catalytic photoredox process provides exceptional yields and selectivities at room temperature. These 1,4-conjugate additions serve as an excellent starting point for synthesizing enantiomerically pure carbon-beta-substituted unnatural alpha-amino acids (UAAs), with potential applications in chemical biology.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Mohammad H. Samha, Julie L. H. Wahlman, Jacquelyne A. Read, Jacob Werth, Eric N. Jacobsen, Matthew S. Sigman
Summary: This study explores hydrogen bond-based organocatalysts using data science tools, revealing the synergistic effect of their structural components and constructing statistical models for predicting high enantioselectivity. The results demonstrate a significant dependence on the identity of the reaction partners and catalysts, and show the predictive capability of the models.
Article
Chemistry, Multidisciplinary
Zubeda Begum, Haruka Sannabe, Chigusa Seki, Yuko Okuyama, Eunsang Kwon, Koji Uwai, Michio Tokiwa, Suguru Tokiwa, Mitsuhiro Takeshita, Hiroto Nakano
Summary: Simple primary beta-amino alcohols act as efficient organocatalysts in the asymmetric Michael addition of beta-keto esters with nitroalkenes, producing highly pure chiral Michael adducts. The choice of catalyst and reaction temperature determines the enantiomeric outcome of the adducts.
Review
Biochemistry & Molecular Biology
Arianna Quintavalla, Davide Carboni, Marco Lombardo
Summary: In 1971, a new asymmetric intramolecular aldol reaction catalyzed by the natural amino acid proline was discovered independently by chemists from Hoffmann-La Roche and Schering AG. This reaction later became known as the Hajos-Parrish-Eder-Sauer-Wiechert reaction. In 2000, it was found that L-proline could also catalyze intermolecular aldol reactions with significant enantioselectivities, and in the same year, imidazolidinones derived from natural amino acids were found to efficiently catalyze asymmetric Diels-Alder cycloadditions, marking the birth of modern asymmetric organocatalysis. In 2005, the use of diarylprolinol silyl ethers for the asymmetric functionalization of aldehydes was proposed, further advancing the field of asymmetric organocatalysis.
Article
Chemistry, Organic
Paula Oroz, Claudio D. Navo, Alberto Avenoza, Jesus H. Busto, Francisco Corzana, Gonzalo Jimenez-Oses, Jesus M. Peregrina
Summary: The study introduces a novel method for the chemo- and diastereoselective 1,4-conjugate additions of Se-nucleophiles to a chiral bicyclic dehydroalanine, offering a promising route for the synthesis of enantiomerically pure selenocysteine derivatives with high potential for chemical biology applications.
Article
Chemistry, Organic
Patricia B. Momo, Eduardo F. Mizobuchi, Radell Echemendia, Isabel Baddeley, Matthew N. Grayson, Antonio C. B. Burtoloso
Summary: Enantioselective sulfa-Michael additions to alpha,beta-unsaturated diazocarbonyl compounds have been developed using quinine-derived squaramide as the catalyst. This method allows the formation of C-S bonds with high stereoselectivity for alkyl and aryl thiols. The synthesis of 22 examples showed enantiomeric ratios up to 97:3 and reaction yields up to 94%. Density functional theory (DFT) calculations were used to determine the mechanism and origins of enantioselectivity.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Applied
Masahiro Sai, Hiroaki Kurouchi
Summary: In this study, the first KHMDS-catalyzed Michael additions of allylic alcohols to alpha,beta-unsaturated amides were reported. The reaction proceeds smoothly with only 5 mol% of KHMDS to afford a variety of 1,5-ketoamides in high yields. Mechanistic investigations revealed that the in-situ generation of the enolate from the allylic alcohol through a tunneling-assisted 1,2-hydride shift is crucial for the success of this transformation.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Physical
Viktoria Kozma, Zsolt Szakonyi, Gyorgy Szollosi
Summary: This study reveals the structural effects of beta-amino acids on the asymmetric Michael additions, including the impact of substituent bulkiness on selectivity, the beneficial arrangement of functional groups in cis isomers, and the influence of nitrogen substituents on reaction rate and enantioselectivity.
Article
Chemistry, Organic
Samira Poorsadeghi, Katsuki Endo, Satoru Arimitsu
Summary: A new enantioselective fluorination method using beta, beta-diaryl serines as a primary amine organocatalyst has been reported, yielding fluorinated products with high yields and excellent enantioselectivity. The presence of the CO2H group in the beta, beta-diaryl serines is found to be crucial for inducing the high enantioselectivity in the reaction.
Review
Chemistry, Organic
Xabier del Corte, Edorta Martinez de Marigorta, Francisco Palacios, Javier Vicario, Aitor Maestro
Summary: Chiral phosphoric acids (CPAs) are efficient organocatalysts that have been widely used for enantioselective additions to C=O and C=N bonds.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Arianna Quintavalla, Davide Carboni, Maria Simeone, Marco Lombardo
Summary: An efficient enantioselective synthesis of chiral alpha-disubstituted beta-homoprolines was developed by utilizing the stereodivergent allylation reaction of chiral N-tert-butanesulfinyl imines derived from 4-bromobutanal with indium or zinc catalysts. This methodology allows for easy introduction of different substituents at the alpha-position of the pyrrolidine scaffold and offers the flexibility to switch the absolute configuration of the newly formed stereocenter by altering the chiral auxiliary or the allylation protocol.
Article
Chemistry, Organic
Arianna Quintavalla, Davide Carboni, Maria Simeone, Marco Lombardo
Summary: An efficient enantioselective synthesis of chiral alpha-disubstituted beta-homoprolines has been developed, allowing for easy introduction of different substituents at the alpha-position and switching of the stereocenter's absolute configuration.
Article
Chemistry, Organic
Viera Polackova, Dominika Kristofikova, Boglarka Nemethova, Renata Gorova, Maria Meciarova, Radovan Sebesta
Summary: Bifunctional N-sulfinylureas and thioureas with an appended pyrrolidine unit were synthesized and evaluated as organocatalysts in Michael additions. The N-sulfinyl-urea catalyst was more efficient than the corresponding thiourea, achieving up to 98% ee enantioselectivities for some substrates. The mode of action was elucidated through DFT calculations, confirming a dual activation mode involving enamine activation of aldehydes and hydrogen-bond activation of nitroalkenes.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Jae Yeon Kim, Yea Suel Lee, Do Hyun Ryu
Summary: This study successfully developed a new method to achieve enantioselective radical reactions of alpha, beta-unsaturated carbonyl compounds using visible light irradiation. In this reaction system, the ternary EDA complex and chiral oxazaborolidinium ions as catalysts not only yielded products with high yields, but also achieved high enantioselectivities.
Review
Chemistry, Multidisciplinary
Sandeep Kumar Sharma
Summary: This review provides a comprehensive overview of the successful applications of organocatalysts for the synthesis of agrochemicals. It summarizes the academic and industrial aspects of the organocatalytic approach for both asymmetric and non-asymmetric synthesis of such chemicals.
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
Chemistry, Organic
Diksha Parmar, Ankit Kumar Dhiman, Rohit Kumar, Akhilesh K. Sharma, Upendra Sharma
Summary: In this study, we report a Cp*Co(III)-catalyzed site-selective olefination and oxyarylation of quinoline N-oxides with terminal alkynes. The selectivity is controlled by steric hindrance and electronic factors.
JOURNAL OF ORGANIC CHEMISTRY
(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.
Article
Chemistry, Multidisciplinary
Eric Palomo, Akhilesh K. Sharma, Zhaofeng Wang, Liyin Jiang, Feliu Maseras, Marcos G. Suero
Summary: We report the first successful generation of Fischer-type acyloxy Rh(II)-carbenes from carboxylic acids and Rh(II)-carbynoids. This novel class of transient donor/acceptor Rh(II)-carbenes evolves through a cyclopropanation process and allows access to densely functionalized cyclopropyl-fused lactones with excellent diastereoselectivity. DFT calculations were performed to analyze the properties of both Rh(II)-carbynoids and acyloxy Rh(II)-carbenes, as well as to characterize the reaction mechanism.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
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
Diksha Parmar, Tamanna Sharma, Akhilesh K. K. Sharma, Upendra Sharma
Summary: A concise method for Rh(iii)-catalyzed, directing-group-assisted C-H/C-H cross-coupling of N-heterocycles (quinolines, indolines, indoles, pyridines, pyrimidines, pyrazoles) with other heteroarenes (benzoxazoles, benzofurans, and thiophenes) is disclosed for the synthesis of unsymmetrical heterobiaryl compounds in good to excellent yields. A plausible catalytic cycle has been delineated based on experimental and computational mechanistic studies.
CHEMICAL COMMUNICATIONS
(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.