Article
Chemistry, Physical
Hyeonji Oh, Bokyeong Ryou, Jinhwi Park, Minju Kim, Jun-Ho Choi, Cheol-Min Park
Summary: By utilizing visible light photocatalysis, we successfully reported the synthesis of pyrrolizidinones through intramolecular imine-alkyne [2 + 2] cycloaddition. This reaction involves imine-alkyne metathesis and subsequent rearrangement, with the proposed reaction mechanisms supported by both control experiments and DFT calculations.
Article
Chemistry, Applied
Shiyong Peng, Hong Zhang, Yuqi Zhu, Ting Zhou, Jieyin He, Nuan Chen, Ming Lang, Hongguang Li, Jian Wang
Summary: A copper-catalyzed tandem reaction was reported for the synthesis of oxapolycyclic frameworks via intermolecular ylide formation and intramolecular cycloaddition, providing moderate to excellent yields under mild conditions. The reaction creates two C-C bonds and one C-O bond, with five stereocentres including two all-carbon quaternary centres. Late-stage diversification of products can be achieved through chemoselective substitutions.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Genlai Zhou, Jingwen Su, Tianbo Shang, Xiaojuan Wang, Yihui Bai, Zheliang Yuan, Gangguo Zhu
Summary: A novel transformation of N-allyl ynamides was developed, enabling the synthesis of nitrogen-fused tricyclic compounds under mild reaction conditions through cascade reactions. This represents a rare example of 4-exo-dig radical cyclization, providing a new opportunity for the construction of synthetically appealing azetidines from readily available N-allyl ynamides.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Taiki Morita, Non Ito, Hiroyuki Nakamura
Summary: Enantioselective dearomative cycloadditions of 4-nitroisoxazoles with vinylethylene carbonate (2) in the presence of Pd-2(dba)(3) and (S)-DTBM-SEGPHOS afforded the corresponding bicyclic isoxazolines 3 and 4 in good to high yields with excellent enantioselectivities (& LE;99% ee). This method was also applicable to the reactions of N-tosyl vinyl aziridine and 2-methylidenetrimethylene carbonate. Further transformations of the resulting cycloadducts 4a and 4i led to the derivatives 10 and 11, as well as the novel tetracyclic skeleton 12.
Article
Chemistry, Organic
Xiaoxue Tang, Zhishan Su, Liqiao Yan, Qiong Tang, Shunxi Dong, Lili Lin, Xiaoming Feng
Summary: Highly diastereo- and enantioselective allylation of isatins with 3-substituted allylboronic compounds was achieved using the chiral N,N'-dioxide/Lu(OTf)(3) complex, leading to enantioenriched 3-allyl-3-hydroxyoxindoles with adjacent tetrasubstituted tertiary or tetrasubstituted quaternary stereogenic centers. The synthetic utility of the reaction was demonstrated by further transformation of the product to a tetrahydrofuranyl oxindole derivative.
Article
Chemistry, Organic
Kou Onodera, Ryo Takashima, Yumiko Suzuki
Summary: This study utilized acylals as building blocks for selective cross-benzoin synthesis via N-heterocyclic carbene-catalyzed reactions, successfully synthesizing O-acyl cross-benzoins. The combination of ortho-substituted phenyl acylals and aromatic/aliphatic aldehydes as coupling substrates using bicyclic triazolium salts as precatalysts and potassium carbonate as a base in THF at reflux temperature selectively yielded the desired products.
Article
Chemistry, Organic
Piotr Szczesniak, Bartlomiej Furman
Summary: An efficient method for the synthesis of bicyclic iminosugars has been developed, involving partial reduction and tandem stereoselective nucleophile addition to form polyhydroxylated cyclic amines. Introduction of vinyl or allyl groups to the iminosugar leads to diene derivatives that can be further converted to polyhydroxylated pyrrolizidine, indolizidine, and quinozilidine derivatives through ring-closing metathesis reaction, with good to excellent yields. This method has been successfully applied to the formal synthesis of hyacinthacine A(2), a polyhydroxylated pyrrolizidine alkaloid.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Mezna Saleh Altowyan, Saied M. Soliman, Matti Haukka, Nora Hamad Al-Shaalan, Aminah A. Alkharboush, Assem Barakat
Summary: In this study, a novel heterocyclic hybrid of a spirooxindole system was synthesized by attaching ferrocene and triazole motifs into an azomethine ylide through a [3 + 2] cycloaddition reaction. The X-ray structure analysis revealed the expected structure of the heterocyclic hybrid and its crystallization in the triclinic-crystal system. Hirshfeld analysis provided insights into the molecular packing and identified the dominant intermolecular contacts in the crystal structure. AIM study indicated covalent characteristics for the Fe-C interactions.
Article
Chemistry, Physical
Leif E. Hertwig, Thilo Bender, Felix J. Becker, Patrick Jaeger, Serhiy Demeshko, Sophie Jana Gross, Joachim Ballmann, Dragos-Adrian Rosca
Summary: We present an efficient iron-catalyzed method for synthesizing conformationally restricted cyclobutane-fused N heterocycles. This method extends the range of substrates and provides a single-step route to previously unattainable cyclobutane-fused piperidines and azepanes. Mechanistic investigations suggest that the catalyst design based on an electron-deficient, redoxactive, pyrimidinediimine scaffold enhances catalyst stability and reaction rate.
Article
Chemistry, Organic
Manickam Bakthadoss, Mohammad Mushaf, Vishal Agarwal, Tadiparthi Thirupathi Reddy, Duddu S. Sharada
Summary: An efficient protocol for the synthesis of tricyclic pyrrolidinochromenes has been developed via an intramolecular 1,3-dipolar cycloaddition. The reaction is highly regio- and diastereoselective, providing potentially bioactive compounds with two rings and four stereogenic centers.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Physical
Ken Yamazaki, Pablo Gabriel, Graziano Di Carmine, Julia Pedroni, Mirxan Farizyan, Trevor A. Hamlin, Darren J. Dixon
Summary: This study discusses an iridium-catalyzed method for the reductive generation of azomethine ylides and their use in pyrrolidine synthesis. The method allows for the efficient access to structurally complex pyrrolidine architectures through subsequent dipolar cycloaddition reactions with variously substituted electron-deficient alkenes. Density functional theory calculations reveal the control of unusual selectivities observed in certain cases by an intimate balance between asynchronicity and interaction energies of transition structures in the cycloaddition reactions.
Article
Chemistry, Organic
Sami Ben Salah, Morgane Sanselme, Yves Champavier, Mohamed Othman, Adam Daich, Isabelle Chataigner, Ata Martin Lawson
Summary: An efficient 1,3-dipolar cycloaddition was reported, involving non-stabilized electron-rich azomethine ylides and diversely substituted 2-pyridones bearing two potential C=C dipolarophilic sites. The reactions occur under mild conditions, leading to the expected cycloadducts with good yields and full control of the regioselectivity. Furthermore, the diastereoselectivity of the second cycloaddition was fully controlled by the first addition, resulting in tricyclo-adducts with a trans relative stereochemistry.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Chaoran Xu, Jianglin Qiao, Shunxi Dong, Yuqiao Zhou, Xiaohua Liu, Xiaoming Feng
Summary: A new bimetallic catalytic system was established for efficient synthesis of chiral heterocycles. The system promoted asymmetric [4 + 3]-cycloaddition reaction, leading to various chiral 4,5-dihydro-1,3-dioxepines in yields up to 97% with 99% ee.
Article
Chemistry, Organic
Vladimir Savych, Vladimir L. Mykhalchuk, Pavlo Melnychuk, Andrii O. Isakov, Taras Savchuk, Vadim M. Timoshenko, Sergiy A. Siry, Sergiy O. Pavlenko, Dmytro Kovalenko, Oleksandr Hryshchuk, Vitalii A. Reznik, Bohdan A. Chalyk, Vladimir S. Yarmolchuk, Eduard B. Rusanov, Pavel K. Mykhailiuk
Summary: A general approach for the synthesis of bicyclic fused pyrrolidines was elaborated using a [3 + 2]-cycloaddition reaction between nonstabilized azomethyne ylide and electron-deficient alkenes. The reaction conditions were optimized to enable the synthesis of novel molecules, including medicinally relevant pyrrolidine derivatives.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Fusun Seyma Gungor, B. Sebnem Sesalan, Nurcan Senyurt Tuzun, Yilmaz Ozkilic, Olcay Anac
Summary: The study highlights the importance of diastereoselectivity in carbenoid reactions, with the synthesized metallophthalocyanine catalysts enabling the enrichment of diastereomeric products. By comparing four different metallophthalocyanines, it was found that copper-Pc with neopentyl is the most effective catalyst.
