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, Multidisciplinary
Keisham Sarjit Singh, Ramila R. Goankar, Kushal Banerjee, Werner Kaminsky
Summary: A series of pyrazolo[5,1-a]isoquinolines were synthesized by ruthenium(II)-catalyzed annulation of pyrazole derivatives with alkynes in the presence of Cu(OAc)(2)?H2O and AgSbF6. The reaction showed high efficiency and yielded excellent products under a nitrogen atmosphere in water. The annulation process could also be carried out in alcohol at a lower temperature without Cu(OAc)(2)?H2O and silver salt, but with the presence of a carboxylate ligand under air. The compounds were characterized by spectroscopic data, and the crystal structure of a representative compound, pyrazolo[5,1-a]isoquinoline derivative, was determined by single-crystal X-ray crystallography.
MONATSHEFTE FUR CHEMIE
(2023)
Article
Chemistry, Organic
Zhi Zhang, Liansuo Zu
Summary: The study successfully synthesized a steroid-sterigmatocystin heterodimer using a concise method, including cascade dialdehyde cyclization, phenol-assisted reductive alkylation, and SNAr reaction. The research also explored a glycosylation-inspired method to provide the acetal linkage with ergosterol peroxide.
Article
Chemistry, Organic
Rui Fu, Ran Liu, Kang Lv, Changlei Zhu, Xiaoguang Bao
Summary: The unprecedented silver-catalyzed desulfurizative annulation of 1,2-benzisothiazoles with ynamides provides a concise protocol for accessing multi-substituted isoquinoline derivatives. Mechanistically, the reaction shows a high degree of chemo- and regio-selectivity, with the N-attack of 1,2-benzisothiazoles on the alkynyl carbon connected with the amide moiety of ynamides being more feasible according to DFT calculations. The final product is obtained through S-N bond cleavage, annulation, and S-atom extrusion steps driven by aromatization.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Bo Han, Hongmei Jiao, Rong Chen, Yuqi Zhang, Jijiang Wang
Summary: The first example of NHC (N-heterocyclic carbene) ligand-promoted reduction of imines and azobenzenes with a homogeneous silver catalyst is reported. The use of PhSiH3 induces hydrogenation of imines and azobenzenes, and the 1 mol% NHC-Ag precatalyst enables the retention of reducible functionalities and compatibility of sensitive groups, offering a mild and practical method for amine preparation with high turnover numbers (up to 9500). It has also been shown that the IPrAgCl/PhSiH3 combination is responsible for the selective C=O reduction of aldehyde and ketone analogues.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Yi-Hao Li, Yuxin Ouyang, Nikita Chekshin, Jin-Quan Yu
Summary: Pd(II)-catalyzed site-selective beta- and gamma-C(sp3)-H arylation of primary aldehydes is achieved by rational design of L,X-type transient directing groups (TDG). External 2-pyridone ligands are crucial for the observed reactivity. By minimizing the loading of acid additives, the ligand effect is enhanced to achieve high reactivities of the challenging primary aldehyde substrates. Site selectivity can be switched by changing the bite angle of TDG to match the desired palladacycle size, as supported by experimental and computational investigations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Ruirui Zhai, Dan Xu, Lili Bai, Shuojin Wang, Dulin Kong, Xun Chen
Summary: An efficient Rh(III)-catalyzed C-H activation and annulation cascade of primary benzylamines with readily accessible alpha-Cl ketones was developed, providing an easy and robust approach to diverse isoquinolines under air with broad functional group tolerance.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Balakrishna Peddi, Souvik Khan, Rajesh G. Gonnade, Cem B. Yildiz, Moumita Majumdar
Summary: The first examples of intramolecular phosphine-stabilized tetra-coordinated germanium(IV) di-cationic compounds were reported and their properties and catalytic activities were studied.
Article
Chemistry, Organic
Jinhui Gu, Yongxing Zhao, Rui Li, Maozhong Miao
Summary: We describe a simple and direct rhodium(III)-catalyzed allylation-intramolecular hydroamination reaction of 5-arylsubstituted pyrazoles with allyl methyl carbonate to generate a range of 5,6-dihydropyrazolo[5,1-a] isoquinolines involving C-H bond activation and cyclization. This method exhibits good functional group compatibility and complete regioselectivity. Control experiments suggest that C-H cleavage may be the rate-determining step. (c) 2023 Elsevier Ltd. All rights reserved.
TETRAHEDRON LETTERS
(2023)
Article
Chemistry, Organic
Jinghui Zhang, Meng Zhang, Yumeng Shi
Summary: This report presents a metal-free convergent paired electrolysis strategy for the synthesis of alpha-benzyl amine from imines and methylarenes, utilizing both anodic oxidation and cathodic reduction. The key to the success of this electrolysis is the simultaneous matching of desirable half reactions, leading to the desired product.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Applied
Quanzhe Li, Ruixing Liu, Yin Wei, Min Shi
Summary: Through the use of a silver/rhodium relay catalysis strategy, an intramolecular electrophilic cyclization and C-H activation followed by cascade hydrogenation and reductive amination has been developed. This method allows for the synthesis of acylmethylated isoquinoline derivatives with a wide substrate scope, which can be further transformed into core structures of potential drug candidates, and the reaction can be achieved in gram-scale. A reasonable reaction mechanism has been proposed based on a series of control and KIE experiments.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Xiao Zhang, Yang Yu, Wenjie Li, Lei Shi, Hao Li
Summary: A flexible metal-free cascade reaction involving aerobic C(sp(3))-H hydroxylation and decarbonylation with high regioselectivity and functional group tolerance has been established. This indirect hydroxylation approach of N-aryl amides enables the construction of a wide range of valuable secondary alcohols at the a-position of N-aryl amides, providing a supplementary strategy for direct alpha-hydroxylation of simple amides.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Mixiang Tian, Lidong Shao, Xiaosan Su, Xuhong Zhou, Honglei Zhang, Kun Wei, Ruifen Sun, Junliang Wang
Summary: A new method has been developed for selective oxygenation of benzaldehydes and benzylic amines at the ortho positions to prepare fluoroalkyl aryl ethers.
Article
Chemistry, Multidisciplinary
Jinhu Xi, Xinjie Wu, Mengmeng Huang, Jung Keun Kim, Jianye Zhang, Yabo Li, Yangjie Wu
Summary: A mild and efficient visible-light-induced synthesis of C-3 dicarbonyl coumarins was achieved without a photocatalyst, with good yields. Some synthesized compounds were highly sensitive to hydrogen peroxide.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Iliyasu Aliyu Bashir, Sunwoo Lee
Summary: Symmetrical anhydrides can be synthesized from activated amides such as N-benzoylsaccharins and N-Boc-protected benzamides. The reaction of activated amides with H2O in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) at 25 degrees C can efficiently cleave the C-N bond and yield the corresponding symmetrical anhydrides in high yields. Additionally, N-benzoylsaccharins can react with benzoic acid derivatives to generate unsymmetrical anhydrides in high yields.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
