Article
Chemistry, Multidisciplinary
Leijie Zhou, Stefania Perulli, Marco M. Mastandrea, Patricia Llanes, Junshan Lai, Miquel A. Pericas
Summary: A polystyrene-supported version of the Denton catalyst has been developed for catalytic inversion of enantiopure secondary alcohols, showing high yields and enantioselectivity. The functional resin exhibits excellent recyclability and can be easily re-activated for extended use.
Article
Chemistry, Multidisciplinary
Bhaskar B. Dhotare, Sahil Kumar, Amey Wadawale, Sandip K. Nayak, Mukesh Kumar, Dibakar Goswami
Summary: A novel metal-free approach for the synthesis of various 3-substituted-3-arylbenzofuran-2(3H)-ones has been developed via H2SO4-mediated dehydrative substitution, yielding moderate to good yields. Mechanistically, the substitution with the alkoxy group proceeds through a phenolic-hydroxyester intermediate, forming the desired product through cascade dehydration-relactonization steps.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Organic
Hengyuan Li, Linqian Qin, Jia Nie, Huanfeng Jiang, Chuanle Zhu
Summary: For over half a century, deoxygenative substitution of alcohols has been limited to using nucleophiles with a single nucleophilic site. In this study, a fluoroolefin-mediated deoxygenative substitution of both nonactivated and activated alcohols with diverse acidic nucleophiles is demonstrated, enabling the construction of C-S, C-N, C-O, and C-Se bonds with chemo- and enantiospecificity by distinguishing the different nucleophilic sites of the nucleophiles. The formed O-tethered monofluoroalkene serves as the intermediate.
Article
Chemistry, Multidisciplinary
Tatsiana Dalidovich, Jagadeesh Varma Nallaparaju, Tatsiana Shalima, Riina Aav, Dzmitry G. Kananovich
Summary: A new mechanochemical method for nucleophilic substitution of alcohols has been developed, offering advantages in reduced waste generation and higher safety profile.
Article
Chemistry, Multidisciplinary
Bing Xu, Ying Lin, Yang Ye, Li Xu, Tian Xie, Xiang-Yang Ye
Summary: A novel copper-catalyzed thioetherification reaction has been developed to efficiently prepare a variety of thioethers, showing exceptional chemoselectivity under mild and easy-to-operate conditions. Preliminary mechanism studies suggest that the reaction proceeds through a Lewis-acid-mediated S(N)1-type nucleophilic attack.
Article
Chemistry, Physical
Hiroki Miura, Yuka Hachiya, Hidenori Nishio, Yohei Fukuta, Tomoya Toyomasu, Kosa Kobayashi, Yosuke Masaki, Tetsuya Shishido
Summary: Efficient borylation of sp(3) C-O bonds was achieved using supported Au catalysts on TiO2, showing high activity and high yields of boronates without the need for additional additives. The mechanism of the reaction involves the formation of a carbocationic intermediate. The Au/TiO2 catalyst system is characterized by its high activity, reusability, environmental compatibility, and scalability.
Article
Multidisciplinary Sciences
Jian-Hua Liu, Wei Wen, Jian Liao, Qi-Wen Shen, Yao Lin, Zhu-Lian Wu, Tian Cai, Qi-Xiang Guo
Summary: The authors report a catalytic asymmetric alpha-benzylation reaction using a chiral aldehyde as the catalyst. This reaction allows for the synthesis of various unnatural optically active alpha-benzyl amino acids with good yields and enantioselectivities. The method is also applied for the synthesis of two somatostatin mimetics and the proposed structure of natural product hypoestestatin 1.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Grant P. Holmin, Jacob C. Hood, Hongfang Xue, Douglas A. Klumpp
Summary: A series of heterocyclic triaryl methanols were reacted with enol silyl ethers in the presence of ZnCl2, leading to the formation of various functionalized heterocyclic products. The proposed mechanism involves the formation of triaryl carbocation electrophiles with the delocalization of positive charge to positions within the heterocyclic rings, followed by nucleophilic attack at a ring position of the heterocycle.
Article
Chemistry, Organic
Aleksey Zerov, Irina A. Boyarskaya, Olesya Khoroshilova, Irina N. Lavrentieva, Alexander Slita, Ekaterina O. Sinegubova, Vladimir V. Zarubaev, Aleksander V. Vasilyev
Summary: Trimethylsilyl ethers of 1,5-diaryl-3-(trifluoromethyl)pent-1-en-4-yn-3-oles in the superacid TfOH give rise to reactive conjugated CF3-allylic-propargylic cations, which, in the presence of arenes and excess TfOH, lead to the formation of E-1,1,5-triaryl-3-(trifluoromethyl)-pent-2-en-4-ynes and CF3-bicyclic dihydroanthracene derivatives, respectively. These two main reaction pathways are dependent on the nucleophilicity of aryl substituents in CF3-pentenynes and external aromatic molecules.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Wenna Xie, Shiwen Liu, Gerald B. Hammond, Bo Xu
Summary: We have developed a versatile transition metal-free cross-coupling reaction between fluorinated benzyl electrophiles and alkenylboronic acids in the presence of alkali metal salts such as K3PO4. This protocol provides good chemical yields for a wide range of substrates and demonstrates excellent functional group tolerance.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Applied
Surajit Duari, Subrata Biswas, Arnab Roy, Srabani Maity, Abhishek Kumar Mishra, Aguinaldo R. Souza, Asma M. Elsharif, Nelson H. Morgon, Srijit Biswas
Summary: In this study, a catalytic synthetic strategy was developed to access various N-functionalized heterocyclic derivatives. The reaction involves the direct nucleophilic substitution of alcohols followed by X to N alkyl group migration. Methyl trifluoromethanesulfonate was found to be an efficient catalyst for this reaction. The mechanism was elucidated through experiments and DFT calculations.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Sunisa Akkarasamiyo, Hatairat Promsaka Na Sakonnakhon, Punlop Kuntiyong, Poonsakdi Ploypradith, Joseph S. M. Samec
Summary: We report a concise and green total synthesis of 1,4-dideoxy-1,4-imino-L-arabinitol hydrochloride from naturally occurring D-xy-lose. The key step involves a stereospecific substitution of a hydroxy group, without prior derivatization, in which the only byproduct is water. This opens up a novel benign route to iminosugar derivatives with diverse biological activities.
Article
Chemistry, Multidisciplinary
Lucie Finck, Martin Oestreich
Summary: This study presents a chemoselective C(sp(2))-C(sp(2)) coupling of electron-deficient fluorinated arenes and functionalized N-aryl-N'-silyldiazenes as masked aryl nucleophiles. The fluoride-promoted transformation involves in situ generation of aryl nucleophiles with sensitive functional groups followed by a stepwise SNAr reaction. These reactions proceed rapidly at room temperature, allowing for functionalization of both coupling partners and yielding highly fluorinated biaryls in good yields.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Wei Xiao, Jie Wu
Summary: This review summarizes recent advances in carbocation-catalyzed reactions, discussing the stability of carbocation compounds, their role as catalysts, and their interactions with other reagents. These developments provide an environmentally friendly pathway for the synthesis of valuable compounds.
CHINESE CHEMICAL LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Sixian Lu, Xingyu Chen, Xiaoqiang Chang, Shuaichen Zhang, Dong Zhang, Yifan Zhao, Lan Yang, Yue Ma, Peng Sun
Summary: In this paper, a transition-metal-free arylation and alkenylation reaction between unprotected allylic alcohols and boronic acids is reported. The reactions were performed with B(C6F5)(3) as the catalyst in toluene, and corresponding products were obtained in 23-92% yields. The reaction has mild conditions, scalability, excellent atom and step economy.
Article
Chemistry, Organic
Manas Jyoti Sarma, Sana Jindani, Bishwajit Ganguly, Srihari Pabbaraja, Goverdhan Mehta
Summary: An efficient protocol for the synthesis of orthogonally strap diynones through one pot transition-metal-free reaction has been developed. Insights into the regioselective tandem Michael-anti-Michael processes have been gleaned through DFT calculations.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
P. Srihari, Y. Bharath Kumar, B. Suresh
ORGANIC PREPARATIONS AND PROCEDURES INTERNATIONAL
(2022)
Article
Chemistry, Organic
Ravi Gurram, Srihari Pabbaraja
Summary: A stereoselective synthetic strategy for (+)-paecilomycin F was developed using readily available 2,4,6-trihydroxy benzoic acid and chiral R(+)-propylene oxide. The synthesis involved key reactions such as regioselective Grignard reaction, Wittig reaction, Sharpless asymmetric dihydroxylation, Barbier-type allylation, Stille-coupling, and ring-closing metathesis. The target molecule was successfully synthesized in a 7-step linear sequence with a 20% overall yield starting from 2,4,6-trihydroxy benzoic acid, or a 12-step sequence with a 12.95% overall yield starting from R(+)-propylene oxide.
LETTERS IN ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
N. K. Chouhan, Sudarshana K. Ananthabhat, Sandeep Vaidya, P. Srihari
Summary: A highly efficient and scalable process for the synthesis of novoldiamine and hydroxynovaldiamine from levulinic acid has been achieved. These compounds are crucial intermediates for the synthesis of antimalarial drugs chloroquine, hydroxychloroquine, and mepacrine.
SYNTHETIC COMMUNICATIONS
(2022)
Article
Biochemistry & Molecular Biology
Ganesh Kumar Raut, Genji Sukumar, Moumita Chakrabarti, Jolly Janette Mendonza, Srihari Pabbaraja, B. Jagan Mohan Reddy, Ramakrishna Sistla, Sai Balaji Andugulapati, Manika Pal Bhadra
Summary: Polyphenols are natural compounds with anti-tumorigenic effects. This study designed and synthesized a compound that interferes with the cell cycle progression in aggressive prostate cancer. Further experiments showed that the compound inhibits the viability of prostate cancer cells and induces apoptosis through oxidative stress. In a mouse model, the compound showed no toxicity and reduced the tumor burden.
Review
Chemistry, Organic
Saumitra Sengupta, Srihari Pabbaraja, Goverdhan Mehta
Summary: Recursive Anionic Cyclization (RAC) is a mechanistically distinct domino strategy that continues to grow. By using nitroalkanes as a source of recursive carbanions, it has created a unique operating space for generating molecular complexity and diversity. The recursive nitronate cyclization, based on a domino [5 C+1 C] cyclization strategy, allows rapid access to densely functionalized carbo- and heterocycles with multiple chiral centers and regio-, stereo- and enantioselectivity. Extension to aromatic domains, particularly through benzannulation reactions, has further expanded the operating space. The functional versatility of nitro group has also been leveraged for post-domino modifications, leading to total synthesis of various natural products.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Srihari Pabbaraja, Bharath Kumar Yasam
Summary: A flexible stereoselective and convergent cum divergent approach to the synthesis of two 13-membered macrolides through a common skeleton is described. The synthesis is achieved using two different routes, resulting in a good overall yield. Key synthetic reactions include Keck allylation, Evans asymmetric methylation, Grubbs metathesis, and Julia-Kocienski olefination.
Article
Chemistry, Organic
Bhushan Mahajan, Dnyaneshwar Aand, Mandeep Purwa, Taufiqueahmed Mujawar, Subhash Ghosh, Srihari Pabbaraja, Ajay K. Singh
Summary: Researchers have used a nanotextured Ni@Cu material embedded electro microflow reactor to synthesize biphenyls in a fast and efficient manner, without the use of noble metals. By optimizing the reactor volume and integrating the process system, they have successfully achieved gram-scale biphenyl synthesis and continuous microflow synthesis of daclatasvir.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Physical
Deepak Kumar Jaiswal, Dnyaneshwar Aand, Puchakayala Krishna Rao, Sibaji Nandi, Srihari Pabbaraja, Ajay K. Singh
Summary: The deactivation of toxic gases and the separation of liquids through metal-organic frameworks (MOFs) have made significant advancements in this growing field. However, the stability of MOFs and their sensitivity to water are still being developed. In this study, a new strategy using scalable and safely generated continuous flow diazomethane is proposed to seal moisture-sensitive functionality in hydrophobic MOFs, demonstrating improved hydrophobicity and its applications in organic/aqueous phase separation and self-cleaning. This work presents the first attempt to seal sensitive functional groups with diazomethane for hydrophobic MOFs, exploring a new proof of concept for designing stable MOFs with controlled wettability. The concept of MOF diazomethane treatment can also be expanded to design and develop advanced membranes for effectively separating aqueous organic solutions, providing valuable insights.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Organic
Manas Jyoti Sarma, K. A. Sudarshana, Goverdhan Mehta, Pabbaraja Srihari
Summary: This study reveals the discovery of reaction regime controlled product diversification in a one-pot reaction between diynones and dimethyl-1,3-acetonedicarboxylate (DMAD), which selectively furnishes either functionally unique pentasubstituted o-alkynylbenzoates or fully substituted furan-3(2H)-ones. Furthermore, the potential of these two versatile platforms to enter new utilitarian chemical space has been explored.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Manas Jyoti Sarma, K. A. Sudarshana, Srihari Pabbaraja, Goverdhan Mehta
Summary: Spiroannulation of oxindole-3-oxy acrylates with ynones involving two overlapping, base differentiated cascades has been observed. The initial tandem Michael-Michael cascade delivers a pair of spiroannulated diastereomers, while a second multistep cascade involving stereoselective restructuring leads to the formation of 3H-spiro[furan-2,3'-indolin]-2'-ones with functional amplification and scrambling. This new scaffold can be synthesized in one flask from ynones and oxindole-3-oxy acrylates.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Saumitra Sengupta, Srihari Pabbaraja, Goverdhan Mehta
Summary: Intrusion into the C-H chemical space of natural products through C-H functionalization reactions can create new molecular diversities and impact biological functions. Semisynthetic C-H modification of natural products is becoming a minimalistic approach in drug discovery. Examples of C-H modification of natural products resulting in improved pharmacological attributes and opportunities in allied areas continue to be reported. This article highlights the evolving paradigm of natural product and synthetic chemistry research to accelerate and broaden natural product-based drug discovery.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Naresh Gantasala, Corentin Fournet, Myriam Le Roch, Claudia Lalli, Srihari Pabbaraja, Nicolas Gouault
Summary: A novel approach for constructing 2-spiropiperidine moieties was developed using dihydropyridones. The addition of allyltributylstannane onto dihydropyridones promoted by triflic anhydride resulted in the formation of gem bis-alkenyl intermediates, which were then converted to the corresponding spirocarbocycles through ring closing metathesis with high yields. The vinyl triflate group generated on these 2-spiro-dihydropyridine intermediates could be successfully utilized as a chemical expansion vector for Pd-catalyzed cross-coupling reactions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Medicinal
Mani Sharma, S. S. S. S. Sudha Ambadipudi, Neeraj Kumar Chouhan, V. Lakshma Nayak, Srihari Pabbaraja, Sai Balaji Andugulapati, Ramakrishna Sistla
Summary: Therapeutically active lipids in drug delivery systems can enhance the safety and efficacy of treatment. The liposome formulation created using synthesized biologically active lipids showed additive anti-cancer effects and reduced tumorigenic potential.
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
(2024)
Article
Chemistry, Multidisciplinary
Gandhari Kishor, Vankudoth Ramesh, Vadithya Ranga Rao, Srihari Pabbaraja, Praveen Reddy Adiyala
Summary: An efficient visible-light driven continuous-flow C-3-alkylation of quinoxalin-2(1H)-ones was achieved using Katritzky salts as alkylating agents. The reaction was catalyzed by eosin-y and base DIPEA at room temperature. The protocol utilized inexpensive alkyl amines and amino acid feedstocks to synthesize a variety of C-3-alkylated quinoxalin-2(1H)-ones. The reaction was carried out in a PFA capillary microreactor under blue LED irradiation, resulting in excellent yields and shorter reaction times compared to a batch system.