Article
Chemistry, Organic
Jie Ren, Chao Pi, Xiuling Cui, Yangjie Wu
Summary: A highly regioselective synthesis of 1-aminoisoquinolines was achieved through Rh(III)-catalyzed reactions, using imidamide as the directing group to achieve high selectivity. This strategy provides a new approach for the synthesis of biologically active 1-aminoisoquinolines.
Article
Chemistry, Multidisciplinary
Sanjeev Kumar, Ajay K. Singh
Summary: The study presents the development of a visible-light-driven modular micro-flow reactor for the synthesis of a fused N-heteroaryl scaffold and late-stage functionalization of pyrazolopyridines. The method offers a simple and efficient approach without the need for expensive oxidants or additional photo-catalysts.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Sundaramoorthi Sarathkumar, Veerababurao Kavala, Ching-Fa Yao
Summary: A water-soluble and low-valent rhenium(I) catalyst has been described for the C2 alkenylation of N-pyridyl/N-pyrimidyl indole derivatives with ynamides under mild conditions using water as the solvent. The reaction results in high yields of C2-Z-selective alkenylation products.
Article
Chemistry, Organic
Rajshekhar A. Unhale, Milon M. Sadhu, Vinod K. Singh
Summary: A novel organocatalytic asymmetric formal [3 + 2] cycloaddition has been developed for the synthesis of biologically relevant chiral spiroisoindolinone-indolines with excellent yields and enantioselectivity under mild conditions.
Article
Chemistry, Organic
Demao Chen, Changfeng Wan, Yunyun Liu, Jie-Ping Wan
Summary: A facile and practical method for the synthesis of fused tricyclic pyrazolo[5,1-a]isoquinolines has been developed via the reactions of enaminones, hydrazine hydrochloride, and internal alkynes using Rh catalysis. The cascade reactions demonstrate the remarkable high-order bond functionalization, involving the transformation of aryl C-H, ketone C=O, and alkenyl C-N bonds in the enaminones. This study highlights the individual advantage of enaminones in the design of novel and efficient synthetic methods.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Sujin Min, Taeeun Kim, Taejoo Jeong, Junhyeok Yang, Yebin Oh, Kyeongwon Moon, Amitava Rakshit, In Su Kim
Summary: The synthesis of functionalized carbazoles has become an important topic in drug discovery and material science. In this study, a rhodium(III)-catalyzed cross-coupling reaction between indolyl nitrones and 2-methylidene cyclic carbonate was disclosed, resulting in the formation of C2-formylated carbazoles. The synthetic utility of this protocol was demonstrated by various post-transformations of C2-formylated carbazoles.
Article
Chemistry, Organic
Suresh Kumar Yadav, Balu Ramesh, Masilamani Jeganmohan
Summary: This study describes an air-stable, highly abundant, and cost-effective Co(III)-catalyzed redox-neutral [4 + 2] annulation reaction of aromatic sulfoxonium ylides with 1,3-diynes, resulting in the synthesis of useful substituted 1-naphthol derivatives in a regioselective manner. Furthermore, the prepared 1-naphthols with internal alkynes were converted into polycarbocyclic molecules and spiro-dienone derivatives with high yields. A possible reaction mechanism involving ortho C-H activation as a key step was proposed and supported by deuterium labeling and kinetic isotope labeling studies.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Alfredo Pereira, Camilo Albornoz, Oleksandra S. Trofymchuk
Summary: This study presents a data-driven approach to analyze reactions catalyzed using [Cp*Co(CO)I-2]. By analyzing different parameters, the screening process in the laboratory is accelerated to yield favorable combinations. The research also demonstrates the effects of reaction conditions and directing groups on the reaction performance.
Article
Chemistry, Organic
Wen-Bi Hu, Yan-Qing Qiu, Wen-Yi Wei, Qing Li, Yan-Jun Xu
Summary: In this study, novel complex C2-quaternary-indol-3-one units bearing versatile nitro groups were successfully developed from pseudo-indolones and alpha,beta-unsaturated nitroolefins through rhodium-catalyzed C-H activation/[3 + 2] spirocyclization. Notably, four diastereomers could be selectively obtained in the reaction by condition control.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Hai-Shan Jin, Cai-Cai Liang
Summary: This study reports an efficient synthesis of isoindolinone-derived spiroisochromenes using a [3 + 3] annulation of 3-aryl-3-hydroxyisoindolinones. In this Rh(iii)-catalyzed spirocyclization reaction, vinylene carbonate acts as a three-atom synthon (C-C-O) through decarboxylation. This atom-economic reaction undergoes through a C-H activation pathway under mild conditions and represents the first example of using 3-aryl-3-hydroxyisoindolinones as building blocks for constructing spiroheterocycles.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Yidi Li, Huiying Xu, Zhi Zhou, Lin Huang, Zhenhao Tang, Wei Yi, Xiaowei Wu
Summary: Efficient cascade reactions are highly desirable for their step-economy and convenience in synthesizing complex molecules. This article reports a rare four-step tandem reaction to prepare difficult-to-synthesize furo[3,4-c]pyridine-1,4-diones using acrylamides and 4-hydroxy-2-alkynoates. The reaction involves C-H activation, Lossen rearrangement, annulation, and lactonization, and offers good functional group tolerance, simple product isolation, and compatibility with room temperature and air. DFT calculations were conducted to understand the reaction mechanism.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Juntao Yang, Bingxian Liu, Junbiao Chang
Summary: A ruthenium(II)-catalyzed one-pot synthesis of highly substituted 1,2-dihydropyridines (DHPs) via a three component reaction system has been successfully developed. The reaction utilizes a simple Ru(II) catalyst without the need for specific ligands. The catalytic system shows excellent functional group compatibility with a wide range of starting materials. The obtained DHPs can be easily converted into tetrahydropyridines and azabicyclo[4.2.0]octa-4,7-dienes by subsequent reduction or [2 + 2] cycloaddition reaction.
Article
Chemistry, Organic
Prakriti Dhillon, Prasad Anaspure, Jesper G. Wiklander, Subban Kathiravan, Ian A. Nicholls
Summary: The regiochemical outcome of a cobalt(ii) catalysed C-H activation reaction of aminoquinoline benzamides with unsymmetrical 1,3-diynes under relatively mild reaction conditions can be controlled by the choice of diyne. The choice of diyne allows access to either 3- or 4-hydroxyalkyl isoquinolinones, facilitating the synthesis of more complex isoquinolines.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Qinghe Gao, Zhenhua Sun, Qinfei Xia, Ruonan Li, Wenlong Wang, Siwei Ma, Yixin Chai, Manman Wu, Wei Hu, Peter Abranyi-Balogh, Gyorgy M. Keseru, Xinya Han
Summary: A new general synthesis method has been developed to prepare pharmaceutically important azolo[1,5-a]pyrimidines starting from commonly available 3(5)-aminoazoles, aldehydes, and triethylamine. This direct and practical strategy allows the construction of a variety of compounds, including pyrazolo[1,5-a]pyrimidines and [1,2,4]triazolo[1,5-a]pyrimidines, with the capability to synthesize zaleplon, a clinically used drug.
Article
Chemistry, Organic
Bedadyuti Vedvyas Pati, Prateep Singh Sagara, Asit Ghosh, Gopal Krushna Das Adhikari, Ponneri Chandrababu Ravikumar
Summary: The study demonstrates the regioselective annulation of N-amino-7-azaindole with 1,3-diynes catalyzed by ruthenium(II). The bioactive N-amino-7-azaindole serves as a new bidentate directing group to produce a range of 3-alkynylated isoquinolones. The protocol is efficient for both aryl- and heteroaryl-substituted amides, resulting in pharmacologically useful 7-azaindole-based isoquinolones with diverse functionalities.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Md Shafiqur Rahman, Naohiko Yoshikai
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2020)
Article
Chemistry, Multidisciplinary
Junfeng Yang, Yuto Mori, Masahiro Yamanaka, Naohiko Yoshikai
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Organic
Roshayed Ali Laskar, Wei Ding, Naohiko Yoshikai
Summary: Benziodoxole triflate (BXT), a cyclic iodine(III) electrophile, has been discovered to facilitate the rearrangement of propargylic alcohols into alpha,beta-unsaturated ketones with an alpha-lambda(3)-iodanyl group. This transformation, known as iodo(III)-Meyer-Schuster rearrangement, is conducted under mild conditions and is compatible with various functionalized propargylic alcohols, providing a new method for synthesizing multisubstituted enones through Pd-catalyzed cross-coupling.
Article
Chemistry, Organic
Wengang Xu, Mingbo Wu, Naohiko Yoshikai
Summary: A new iron-catalyzed method has been developed for the site-selective alkylation of the quinoline nucleus, which shows good efficiency in producing C5-alkylation products. Based on control experiments, a proposed reaction mechanism involving the addition of an alkyl radical to an iron-chelated intermediate.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Multidisciplinary
Chang-Sheng Wang, Qiao Sun, Felipe Garcia, Chen Wang, Naohiko Yoshikai
Summary: The study presents a simple and inexpensive catalytic system based on cobalt(II) iodide, 1,3-bis(diphenylphosphino)propane, and Zn for the [2+2+2] cycloaddition of various nitriles and diarylacetylenes to synthesize a broad range of polyarylated pyridines. DFT studies support a reaction pathway involving oxidative coupling of two alkynes, insertion of the nitrile into a cobaltacyclopentadiene, and C-N reductive elimination, leading to the synthesis of tetra- and pentaarylpyridines that can be used as precursors for nitrogen-containing polycyclic aromatic hydrocarbons.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Yoshiya Sekiguchi, Naohiko Yoshikai
Summary: An enantioselective conjugate addition reaction using a zinc homoenolate catalytically generated from cyclopropanol and added to an alpha,beta-unsaturated ketone was reported. The reaction produced highly substituted cyclopentene derivatives with good to high enantioselectivities through intramolecular aldol condensation of 1,6-diketones. The use of a chiral amino alcohol as a ligand-accelerated the catalysis of the homoenolate generation and its conjugate addition.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Yoshiya Sekiguchi, Yan Ying Lee, Naohiko Yoshikai
Summary: This work presents a nickel-catalyzed ring-opening allylation of cyclopropanols with allylic carbonates under mild and neutral conditions, showing good yields and linear selectivity. Mechanistic experiments support a catalytic cycle involving several key steps including decarboxylative oxidative addition and C-C reductive elimination.
Article
Chemistry, Multidisciplinary
Yoshiya Sekiguchi, Naohiko Yoshikai
Summary: A zinc-catalyzed beta-allylation of cyclopropanols with Morita-Baylis-Hillman (MBH) carbonates was reported, maintaining the cyclopropane ring and yielding cyclopropyl-fused alpha-alkylidene-delta-valerolactone derivatives. The mechanism involves zinc homoenolate formation and enolization, followed by alpha-allylation with MBH carbonate leading to cyclopropane ring regeneration and irreversible lactonization, allowing for beta-functionalization with alkylidenemalononitrile as well. This reaction provides a pathway to transform simple cyclopropanols into alpha,beta- or beta,beta-difunctionalized ketones.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Chang-Sheng Wang, Ploypailin Siew Ling Tan, Wei Ding, Shingo Ito, Naohiko Yoshikai
Summary: This method efficiently synthesizes beta-iodo(III)enol carboxylates, phosphates, and tosylates through regio- and stereoselective iodo(III) functionalization of alkynes, which can be further used for the synthesis of multisubstituted alkenes.
Article
Chemistry, Organic
Yoshiya Sekiguchi, Naohiko Yoshikai
Summary: The direct and diastereoselective synthesis of vicinal anti-sec,tert-diols has been achieved through zinc-mediated alpha-hydroxyallylation of aldehydes. This reaction shows strong preference for a chelated (Z)-configuration of the enolized homoenolate, leading to the formation of bicyclic chairlike transition states.
Article
Chemistry, Physical
Chang-Sheng Wang, Yongqi Yu, Yusuke Sunada, Chen Wang, Naohiko Yoshikai
Summary: This article reports a cobalt-catalyzed carbo- and hydrocyanation reaction of alkynes, which involves C-CN bond cleavage of organic cyanides. A low-valent cobalt-diphosphine catalyst, generated by reduction with Zn, is used to promote the arylcyanation of alkynes with trans-selectivity. Additionally, the addition of Zn(OTf)2 to the catalytic system accelerates the reaction and switches the stereoselectivity.
Article
Chemistry, Multidisciplinary
Yuri Saito, Jun Kikuchi, Chen Wang, Naohiko Yoshikai
Summary: We report the design and development of Co/Al and Co/Mg bimetallic catalysts supported by a phosphine/secondary phosphine oxide (PSPO) bifunctional ligand for the selective C-H alkenylation of nitrogen-containing heteroarenes with alkynes. These catalysts enable the alkenylation of pyridine, pyridone, and imidazo[1,2-a]pyridine derivatives at the C-H site proximal to the Lewis basic nitrogen or oxygen atom, with a selectivity profile distinct from previously developed cobalt-diphosphine/aluminum catalyst. The alkenylated products were obtained in moderate to good yields using various heterocycles and differently substituted internal alkynes. Kinetic isotope effect experiments suggest the irreversibility of the C-H activation step, the relevance of which to the rate-limiting step depends on the reaction conditions. Density functional theory calculations indicate that ligand-to-ligand hydrogen transfer is the common mechanism of C-H activation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Kento Tsukiji, Takeru Hayakawa, Kazuya Kanemoto, Naohiko Yoshikai
Summary: In this study, a zinc-mediated annulation reaction between cyclopropanols and alkylidenemalononitriles was reported. The reaction was promoted by Et2Zn and 1,4-diazabicyclo[2.2.2]octane (DABCO) in DMSO at 80 degrees C, resulting in the formation of cyclopropane-fused 6-amino-3,4-dihydro-2H-pyran-5-carbonitrile derivatives with moderate to good yields and high diastereoselectivity. The proposed reaction mechanism involves the generation of an enolized homoenolate as the key reactive intermediate through the ring opening of zinc cyclopropoxide and enolization of the resulting zinc homoenolate, followed by Michael addition, ring closure, and intramolecular cyclization.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Shuma Sasaki, Jun Kikuchi, Shingo Ito, Naohiko Yoshikai
Summary: In this study, a method for preparing stereodefined enolates by leveraging the stereoselective oxyfunctionalization of unactivated alkynes and their reaction with aldehydes to form γ,δ-unsaturated β-diketones was described.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jinkui Chai, Wei Ding, Chen Wang, Shingo Ito, Junliang Wu, Naohiko Yoshikai
Summary: The Ritter reaction is a classical method for synthesizing tertiary amides, but the synthesis of enamides through analogous reactions remains challenging. In this study, a new method was reported for the trans-difunctionalization of alkynes with a trivalent iodine electrophile and nitrile to afford beta-iodanyl enamides, where the benziodoxole group in the product serves as a versatile handle for further transformations to prepare other substituted enamides.
