Article
Chemistry, Organic
Andrea Vopalenska, Vojtech Docekal, Simona Petrzelova, Ivana Cisarova, Jan Vesely
Summary: The present study reports an asymmetric organocascade reaction that efficiently catalyzes the reaction between oxindole-derived alkenes and 3-bromo-1-nitropropane using a bifunctional catalyst. The reaction produces spirooxindole-fused cyclopentanes in moderate-to-good isolated yields (15-69%) with excellent stereochemical outcomes. The synthetic utility of the protocol is demonstrated through additional transformations of the resulting spirooxindole compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Nagaraju Kerru, Lalitha Gummidi, Suresh Maddila, Sreekantha B. Jonnalagadda
Summary: The study presents the preparation and characterization of magnesium loaded hydroxyapatite composite, and evaluates its catalytic activity for the synthesis of novel dihydropyrazolo[3,4-b] pyridine derivatives. The composite showed excellent yields, reusability, and simplicity in operation, making it a promising catalyst for organic synthesis.
INORGANIC CHEMISTRY COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Minh-Huy Dinh Dang, Linh Ho Thuy Nguyen, Trang Thi Thu Nguyen, Ngoc Xuan Dat Mai, Phuong Hoang Tran, Tan Le Hoang Doan
Summary: Sulfate-functionalized Hf-based metal-organic frameworks show high catalytic activity and reusability in heterogeneous catalysis applications. They possess a high-porosity framework and high active sites of functionalized clusters, enabling efficient catalysis of substrates under mild, solvent-free conditions.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2021)
Article
Chemistry, Applied
Ben-Jie Jiang, Song-Lin Zhang
Summary: A general method is developed for the synthesis of quinolines and C2-functionalized quinolines from ortho-alkenyl anilines using a difluorocarbene precursor. The method involves the in-situ generation of isocyanides from primary aniline and difluorocarbene, which then undergo alpha-addition by neighboring alkenyl groups to form the quinoline ring. In the presence of Se, selenoisocyanate intermediates are generated, leading to the synthesis of 2-SeH quinolines. The method allows for the modular synthesis of various C2-functionalized quinolines in one step, using readily available starting compounds.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Chengkai Luo, Mingzhong Cai, Ruonan Zhao, Bin Huang
Summary: An efficient heterogeneous copper(I)-catalyzed three-component tandem cyclization reaction has been developed using 3-(2-aminoethylamino)propyl-modified MCM-41-bound copper(I) bromide as the catalyst. The reaction proceeded smoothly in DMSO at 120 degrees C and delivered polysubstituted pyridines in good to high yields. The catalyst can be easily prepared from commercially available and inexpensive reagents and reused multiple times without loss of catalytic efficiency.
SYNTHETIC COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Wu-Lin Yang, Jia-Huan Shen, Zeng-Hui Zhao, Zhongao Wang, Wei-Ping Deng
Summary: In this study, a gold/palladium bimetallic relay catalytic strategy was developed for the synthesis of furan-fused azepines with excellent enantioselectivities. Enynamides were activated by a gold catalyst to generate azadienes in situ, which then reacted with Pd-TMM via the asymmetric [4 + 3] cycloaddition process. Furthermore, oxidative furan cleavage of the cycloadducts mediated by potassium nitrate allowed the synthesis of poly-functionalized enantioenriched azepines under mild conditions.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Naveen Diddi, Dale E. Ward
Summary: The total synthesis of dolabriferol C was achieved by a series of unique chemical reactions, simplifying the synthetic process significantly. This synthetic approach combines different stereochemical selectivities and enantioselective reactions, providing new insights for the study of related compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Yasutaka Ohkubo, Yui Masuda, Yusuke Ogura, Hirosato Takikawa, Hidenori Watanabe
Summary: The enantioselective synthesis of (3S,3aS,7aR)-wine lactone, a major aroma component of white wine and citrus juices, was achieved starting from (S)-2-methyl-3-butenoic acid, with an intramolecular Diels-Alder reaction being employed as a key step.
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY
(2021)
Article
Chemistry, Physical
Ruijie Mi, Xuepeng Zhang, Jinlei Wang, Haohua Chen, Yu Lan, Fen Wang, Xingwei Li
Summary: This study reports the rhodium-catalyzed enantioselective three-component coupling of arene, diene, and dioxazolone via C-H activation to produce chiral allylic amines. The electrophilic amination of the pi-allyl species is both regio- and enantio-determining in this carboamination reaction.
Article
Chemistry, Multidisciplinary
Seoyoung Cho, E. J. McLaren, Qiu Wang
Summary: The difunctionalization of strained cyclic alkynes provides a powerful strategy to construct diverse cyclic alkenes. A new approach using a zincate base/nucleophile system has been demonstrated for efficient formation of cyclohexyne intermediates and selective addition of various carbon and nitrogen nucleophiles, enabling the synthesis of structurally diverse cyclohexene motifs. The modularity and ease of access to highly complex polycyclic scaffolds in one step highlight the importance and utility of this method.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Hasti Amorzesh, Mohammad Bayat, Shima Nasri
Summary: A new class of multi-functional triazole hexahydroquinoline carbohydrazide has been successfully synthesized using a novel multi-component reaction method. The method offers a simple one-pot process, avoiding tedious purification steps, and does not require any catalyst, allowing for diverse molecular structures.
MOLECULAR DIVERSITY
(2022)
Article
Chemistry, Multidisciplinary
Marie Deliaval, Ramasamy Jayarajan, Lars Eriksson, Kalman J. Szabo
Summary: We have developed a new three-component catalytic coupling reaction involving alkynyl boronates, diazomethanes, and aliphatic/aromatic ketones in the presence of BINOL derivatives. This reaction exhibits remarkably high enantio- and diastereoselectivity, leading to the formation of tertiary CF3-allenols with up to three contiguous stereocenters in a single step. The reaction proceeds under mild, neutral, and metal-free conditions, making it highly functional group tolerant.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jia-Yi Shou, Feng-Ling Qing
Summary: This study reports a three-component radical addition reaction for the selective formation of alpha-alkyl-alpha-SF5 carbonyl compounds. The reaction proceeds through the reaction of SF5 radical with diazo compounds, followed by the addition of a carbon radical to alkene. Additionally, the reaction can be used to prepare alpha-allyl-alpha-SF5 carbonyl compounds, and the three-component adducts formed can be converted into pentafluorosulfanylfurans.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Hirofumi Ueda, Ryota Yamamoto, Minami Yamaguchi, Hidetoshi Tokuyama
Summary: A three-component reaction for the synthesis of substituted anilines was developed using a gold(I)-catalyzed domino reaction. The reaction involved sequential activation of two different alkynes, resulting in a variety of substituted anilines. The utility of the aniline products was further demonstrated by derivatization to substituted benzoxazines.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Review
Chemistry, Organic
Suven Das
Summary: This review highlights novel stereoselective strategies for the synthesis of various heterocycles using isoquinolinium salts. These reactions offer advantages such as high stereoselectivity, readily available starting materials, and mild reaction conditions, and have been successfully used in the synthesis of natural products and bioactive compounds.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Applied
Yi-Ya Zhang, Ramani Gurubrahamam, Kwunmin Chen
ADVANCED SYNTHESIS & CATALYSIS
(2015)
Review
Chemistry, Physical
Ramani Gurubrahamam, You-Song Cheng, Wan-Yun Huang, Kwunmin Chen
Article
Chemistry, Organic
Ramani Gurubrahamam, Bing-Fong Gao, Yan Ming Chen, Yu-Te Chan, Ming-Kang Tsai, Kwunmin Chen
Article
Chemistry, Organic
Ramani Gurubrahamam, Yan Ming Chen, Wan-Yun Huang, Yu-Te Chan, Hsiang-Kai Chang, Ming-Kang Tsai, Kwunmin Chen
Article
Chemistry, Multidisciplinary
Ramani Gurubrahamam, Koppanathi Nagaraju, Kwunmin Chen
CHEMICAL COMMUNICATIONS
(2018)
Article
Chemistry, Organic
Marcus Reitti, Ramani Gurubrahamam, Melanie Walther, Erik Lindstedt, Berit Olofsson
Article
Chemistry, Applied
Wan-Yun Huang, Ramani Gurubrahamam, Kwunmin Chen
ADVANCED SYNTHESIS & CATALYSIS
(2019)
Review
Chemistry, Organic
Akashdeep Sharma, Koppanathi Nagaraju, Gunda Ananda Rao, Ramani Gurubrahamam, Kwunmin Chen
Summary: This review highlights the enantioselective organocatalytic protocols for the functionalization of electron-deficient internal alkynes and enynes. It discusses the use of activated conjugated pi-systems in asymmetric synthesis for providing diversified chiral entities under metal-free reaction conditions, demonstrating various organocatalytic strategies with different catalytic modes.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Gunda Ananda Rao, Ramani Gurubrahamam, Kwunmin Chen
Summary: An efficient protocol for base-catalysed (4+2) annulation between 2-nitrobenzofuran and N-alkoxyacrylamide was developed, yielding 1-alkoxy-3,4-dihydrobenzofuro[3,2-b]pyridin-2(1H)-ones by organic base catalysis and dearomative nitrotetrahydrobenzofuro[3,2-b]pyridin-2(3H)-ones in the presence of an inorganic base. The advantages of this methodology include easily accessible starting materials, simple operational procedures, broad substrate scope, and synthetically useful yields at milder reaction conditions.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Organic
Paru Jamwal, Himani Vaid, Gunda Ananda Rao, Ramani Gurubrahamam, Kwunmin Chen
Summary: This review explores the asymmetric organocatalytic reactions of various electron-deficient racemic allenes with nucleophiles and electrophiles. It presents the literature on enantioselective functionalization of allenes using chiral phosphine, amine, phase transfer, bifunctional, and Bronsted acid catalysts, along with their mechanisms. The review also highlights the methods of obtaining enantioenriched allenes from racemic allenes through organocatalytic (dynamic) kinetic resolution techniques. Furthermore, it narrates the synthetic utility of these methodologies in the synthesis of target-oriented biologically active molecules.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Gunda Ananda Rao, Paru Jamwal, Ramani Gurubrahamam, Kwunmin Chen
Summary: An efficient metal-free method for the formal alkenylation and amination of 2-nitrobenzofurans was achieved through the use of inorganic base promoted fumaric acid amide ester derivatives. The cascade reaction sequence involving Michael addition, cyclization, nitrous acid elimination, N-demethoxylation, C-N bond cleavage, and isomerization provided 2-alkenyl and 3-amino substituted benzofuran derivatives. The desired 2-(3-aminobenzofuran-2-yl)malonate derivatives were obtained with moderate-to-good yields and high stereoselectivity. The structure of the products was confirmed by single crystal x-ray structural analysis.
Article
Chemistry, Organic
Akashdeep Sharma, Paru Jamwal, Himani Vaid, Ramani Gurubrahamam
Summary: Alkynyl hydrazones can be conveniently synthesized from 2-oxo-3-butynoates and hydrazine by suppressing the formation of pyrazoles. The resulting hydrazones can then be transformed into alkynyl diazoacetates under metal-free and mild oxidative conditions, giving excellent yields. In addition, alkynyl cyclopropane and propargyl silane carboxylates are synthesized in good yields by a novel copper-catalyzed alkynyl carbene transfer reaction.
Article
Chemistry, Organic
Akashdeep Sharma, Paru Jamwal, Ramani Gurubrahamam
Summary: This study presents a highly efficient and stereoselective route for the synthesis of 1,4-dicarbonyl 2,3-dihaloalkenes. By using stable unprotected alkynyl hydrazones and commercially available N-halosuccinimides, gamma-oxo-alpha, beta-(Z)-dihaloenoates were successfully obtained with high yields and complete Z-selectivity. The protocol also allows for the synthesis of vicinal dihaloalkenes with two different halogen atoms. In addition, a straightforward one-pot synthesis of dihaloenoates from readily accessible compounds was demonstrated, and potential applications of 4-oxo-2,3-dibromoenoates were explored, including the synthesis of valuable five- and six-membered heterocycles.
Article
Chemistry, Organic
Paru Jamwal, Akashdeep Sharma, Ramani Gurubrahamam
Summary: An unprecedented decomposition of unprotected alkynyl hydrazones yields allenoates, tetrasubstituted a,?-dihaloallenoates, and functionalized tricyclic azepines. The reaction with N-halosuccinimides produces dibromo- and diiodoallenoates, while a DABCO-promoted Wolff-Kishner reduction followed by isomerization provides versatile allenoates. On the other hand, decomposition with ambiphilic DBU affords a different tricyclic azepine scaffold.
Article
Chemistry, Applied
Fu-Jie Chang, Ramani Gurubrahamam, Kwunmin Chen
ADVANCED SYNTHESIS & CATALYSIS
(2017)
