Article
Chemistry, Multidisciplinary
Wei Liu, Tianren Qin, Wansen Xie, Jinmiao Zhou, Zidan Ye, Xiaoyu Yang
Summary: We have developed an efficient modular asymmetric synthesis of azahelicenes from readily available polycyclic aromatic amines, aldehydes, and (di)enamides, employing a central-to-helical chirality conversion strategy. A series of aza[5]- and aza[4]helicenes bearing various substituents were easily obtained with good yields and high enantioselectivities. The diverse derivatizations and the preliminary application of the azahelicene derivative as a chiral organocatalyst demonstrated the potential of this method, and the photophysical and chiroptical properties of these azahelicenes were well studied, showing potential applications in novel organic optoelectronic materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Eugenia Marques-Lopez, Isaac G. Sonsona, Miryam Garces-Marin, M. Concepcion Gimeno, Raquel P. Herrera
Summary: In this study, the potential of phosphites as nucleophiles for the asymmetric synthesis of chiral chromene derivatives was explored. By employing asymmetric organocatalyzed phospha-Michael addition, chiral chromenylphosphonates were synthesized using a bifunctional squaramide. The optimized protocol provided good reactivity with yields of up to 95% and chiral products with an enantiomeric excess of up to 98%.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Review
Chemistry, Multidisciplinary
Cheng Niu, Da-Ming Du
Summary: This review highlights the recent advancements in sulfa-Michael addition-triggered cascade reactions for the stereoselective synthesis of sulfur-containing compounds. It discusses various types of reactions, including sulfa-Michael/aldol, sulfa-Michael/Henry, sulfa-Michael/Michael, sulfa-Michael/Mannich and some sulfa-Michael triggered multi-step processes. The review also introduces reaction mechanisms and derivatization experiments.
Article
Chemistry, Multidisciplinary
Poorna Chandrasekhar Settipalli, Shaik Anwar
Summary: A [2+2+2] annulation reaction between cyclohexanone, beta-nitrostyrene and 2-arylidene-1,3-indanedione has been successfully carried out to obtain multisubstituted spiro trans-decalinol derivatives at room temperature. This reaction process exhibits high chemical yields and excellent diastereoselectivity, resulting in the formation of multiple bonds and stereocenters through the Michael/nitro-Michael/Aldol process.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Applied
Irma Garcia-Monzon, Jorge Borges-Gonzalez, Tomas Martin
Summary: The heterogenization of homogeneous catalysts onto a solid support is a crucial step towards sustainable chemistry. In this study, we developed a series of polymer-supported tetrahydropyran-based hybrid dipeptides as active catalysts for the enantioselective Michael addition of aldehydes to beta-nitrostyrenes. The optimal anchor position and orientation between the catalyst and solid support, as well as the linker length, were carefully designed to enhance the catalytic efficiency. These supported catalysts exhibited high yields and enantiomeric excesses, and detailed deactivation studies provided important insights for prolonging their useful life.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Yongkang Song, Jian Wang, Shaomin Deng, Guohua Liu, Tanyu Cheng
Summary: Domino catalytic reactions are a powerful strategy for synthesizing complex and high-value compounds. In this study, a domino enantioselective Michael addition/cyclization process, catalyzed by inexpensive and readily available quinidine, was developed. The reaction proceeded smoothly under mild conditions at room temperature within 2 hours, affording chiral 1,4-dihydro-pyridine containing benzosultams in good yields (up to 95%) and excellent enantioselectivities (up to 99% ee).
MOLECULAR CATALYSIS
(2022)
Article
Chemistry, Applied
Amit Shikari, Koushik Mandal, Deepak Chopra, Subhas Chandra Pan
Summary: A new organocatalytic asymmetric synthesis method has been developed for the synthesis of cyclic acetals with a spirooxindole skeleton. It was found that a bifunctional squaramide catalyst with an adamantyl motif was the most effective in the cascade reaction, providing high diastereo- and enantioselectivities for the desired products.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Muhammad Sohail, Fujie Tanaka
Summary: The DYKAT reactions can transform dihydrobenzofuranone derivatives into spirooxindole derivatives with high enantioselectivities and yields, regardless of the stereochemistry of the starting materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Laura A. Bryant, Kenneth Shankland, Hannah E. Straker, Callum D. Johnston, Nicholas R. Lees, Alexander J. A. Cobb
Summary: The article describes a rare organocatalytic intramolecular cyclization of resorcinols with a high enantioselectivity using a specific organocatalyst. The obtained bicyclic resorcinols show excellent utility in the synthesis of cannabinoid-like compounds, and exhibit anticonvulsant activity.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Xiu-Ning Hu, Dong-Ping Wu, Ye-Peng Xu, Pei-Qiang Huang
Summary: The first organocatalytic asymmetric synthesis of an advanced intermediate of (+)-sarain A was achieved by combining organocatalytic asymmetric Michael addition reaction and a nitrogen-to-carbon chirality transfer. This method allows for the construction of three chiral centers and chemoselective reduction of a key lactam intermediate, providing a tricyclic intermediate with all necessary functionalities for further elaboration into (+)-sarain A.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Martina Sotolova, Martin Kamlar, Marek Remes, Pierre-Yves Geant, Ivana Cisarova, Martin Sticha, Jan Vesely
Summary: An organocatalytic asymmetric domino Michael/alpha-alkylation reaction has been developed for the synthesis of 1,2,3-trisubstituted cyclopentane carbaldehydes. The reaction, catalyzed by chiral secondary amines, exhibits high diastereo- and enantioselectivities.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Ophelie Quinonero, Clement Lemaitre, Marion Jean, Nicolas Vanthuyne, Christian Roussel, Damien Bonne, Thierry Constantieux, Cyril Bressy, Xavier Bugaut, Jean Rodriguez
Summary: This reinvestigation focused on a chiral phosphoric acid-catalyzed synthesis of polyhydroquinolines reported in 2009, revealing a lack of enantioselectivity with the use of chiral enantiopure phosphoric acid catalyst as opposed to the original report. The new Enantioselectivity results were confirmed through baseline separation of enantiomers using HPLC analyses on chiral stationary phase with UV and chiroptical detection.
Review
Chemistry, Applied
Helene Pellissier
Summary: This review provides an update on the field of enantioselective domino reactions catalyzed by chiral catalysts derived from noble metals, such as palladium, silver, rhodium, ruthenium, iridium, and gold, since the beginning of 2019. It showcases the diverse range of these catalysts, enabling unprecedented asymmetric domino reactions with excellent enantioselectivity and providing access to a wide variety of complex chiral molecules.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Fangfang Guo, Jiean Chen, Yong Huang
Summary: Recently, chiral N-heterocyclic carbenes (NHCs) have been established as powerful catalysts for enantioselective bond-forming processes via noncovalent interactions. A bifunctional NHC with an embedded hydrogen-bonding motif has been reported in this study, showing remarkable tolerance of various Michael acceptors in an asymmetric aza-conjugate addition reaction, with catalytic efficiency far exceeding that of the benchmark tertiary amine-thiourea scaffold.
Article
Biochemistry & Molecular Biology
Xiao-Yan Dong, Da-Ming Du
Summary: This paper investigated the organocatalytic asymmetric 1,4-Michael addition reaction of azadienes and alpha-thiocyanoindanones, successfully synthesizing a series of chiral thiocyano compounds. By describing a possible reaction mechanism, it broadens the scope of application of azadiene substrates.
Article
Chemistry, Medicinal
Elvira Hermawati, Suzany D. Ellita, Lia D. Juliawaty, Euis H. Hakim, Yana M. Syah, Hayato Ishikawa
Summary: Two new quinone derivatives isolated from an endophytic fungus from Morus cathayana showed potential as tyrosine kinase inhibitors, displaying particularly strong inhibitory properties against Bruton's Tyrosine Kinase.
JOURNAL OF NATURAL MEDICINES
(2021)
Article
Biotechnology & Applied Microbiology
Syuuto Toyoda, Morihiro Oota, Hayato Ishikawa, Shinichiro Sawa
Summary: The research discovered that some commercial silica gels containing calcium sulfate can attract nematodes, which may be used in agriculture to reduce the prevalence of root-knot nematodes.
PLANT BIOTECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Jukiya Sakamoto, Hayato Ishikawa
Summary: This study reports a series of bioinspired transformations that convert strictosidine aglycones into monoterpenoid indole alkaloids. By removing a silyl protecting group and conducting selective conversions, various monoterpenoid indole alkaloids can be synthesized efficiently.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Shinya Shiomi, Kaewsri Wilailak, Wataru Soutome, Hiromitsu Takayama, Mariko Kitajima, Hayato Ishikawa
Summary: A first asymmetric total synthesis of huperzine H has been achieved in a 12% overall yield from commercially available (+)-pulegone. The relative and absolute stereochemistry of huperzine H is established through key reactions including a highly diastereoselective Mukaiyama-Michael addition reaction and an intramolecular S(N)2 cyclization reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Kazuki Urakawa, Yurie Yatsuoka, Yuta Kawabata, Hyuma Masu, Masaki Matsuda, Hayato Ishikawa
Summary: Borocyclic radicals with highly conjugated aromatics were generated from orthoquinone-containing polycyclic aromatic compounds by trapping the photoinduced triplet state. The stable picene-based borocyclic radical exhibited a unique crystal structure and higher electrical conductivity.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Editorial Material
Chemistry, Organic
Hayato Ishikawa
JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN
(2022)
Article
Nutrition & Dietetics
Mario A. Tan, Hayato Ishikawa, Seong Soo A. An
Summary: The study found that extracts from Pandanus amaryllifolius have potential anti-Alzheimer's disease effects by inhibiting A beta aggregation, reducing oxidative stress, and reversing mitochondrial damage.
Article
Chemistry, Multidisciplinary
Jukiya Sakamoto, Mariko Kitajima, Hayato Ishikawa
Summary: The total syntheses of geissoschizine-type monoterpenoid indole alkaloids (MTIAs) were achieved using various methods such as intramolecular Pictet-Spengler cyclization and aza-Michael cyclization/E1cB elimination/stereoselective olefin isomerization sequence. The synthesis of (+)-villocarine A and (-)-apogeissoschizine were successfully accomplished, and (+)-geissoschizine was obtained through ring-opening from apogeissoschizine.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Akiho Yoshidome, Jukiya Sakamoto, Mizuki Kohara, Shinya Shiomi, Mako Hokaguchi, Yuki Hitora, Mariko Kitajima, Sachiko Tsukamoto, Hayato Ishikawa
Summary: Divergent total syntheses of hetero-oligomeric iridoid glycosides were achieved using efficient synthetic methods. The monomer unit loganin was stereoselectively synthesized through reductive cyclization of secologanin. Sequential condensation reactions of derivatives of loganin and secologanin led to the synthesis of heterooligomers cantleyoside, (E)-aldosecologa-nin, dipsaperine, (3R, 5S)-5-carboxyvincosidic acid 22-loganin ester, and dipsanoside A.
Article
Plant Sciences
Morihiro Oota, Syuuto Toyoda, Toshihisa Kotake, Naoki Wada, Masatsugu Hashiguchi, Ryo Akashi, Hayato Ishikawa, Bruno Favery, Allen Yi-Lun Tsai, Shinichiro Sawa
Summary: A chemoattractant of plant-parasitic root-knot nematodes has been isolated from the Super-growing Root culture system and found to be enriched in carbohydrates, particularly arabinose and galactose. This attractant is essential for the attraction of Meloidogyne incognita but not other nematode species.
FRONTIERS IN PLANT SCIENCE
(2023)
Article
Chemistry, Organic
Yuta Nakashima, Taichi Inoshita, Mariko Kitajima, Hayato Ishikawa
Summary: The first asymmetric total synthesis of the Lycopodium alkaloid senepodine F, containing a decahydroquinoline ring (AB-ring) and a quinolizidine ring (CD-ring) connected by a methylene tether, has been achieved. The key steps of this synthesis involve an organocatalytic asymmetric Diels-Alder reaction, a diastereoselective intramolecular aza-Michael reaction, and an intramolecular SN2 cyclization to construct nitrogen-containing heterocycles. Furthermore, this total synthesis allowed for the reassignment of the stereochemistry of the decahydroquinoline ring in senepodine F.
Article
Chemistry, Organic
Jukiya Sakamoto, Hayato Ishikawa
Summary: The preparation of natural product libraries by total synthesis is an important and attractive research topic in organic chemistry. This Account presents a practical total synthesis of secologanin using an asymmetric organocatalytic cascade reaction. It also describes the collective total synthesis of secologanin-related natural products using reference to biosynthesis. So far, 39 secologanin-related natural products have been successfully synthesized using bioinspired strategies, with the synthetic strategies for 20 of them presented in this Account.
Article
Chemistry, Organic
Jukiya Sakamoto, Daiki Hiruma, Mariko Kitajima, Hayato Ishikawa
Summary: In this study, the collective and efficient asymmetric total syntheses of five beta-carboline-type monoterpenoid indole alkaloid glycosides were successfully achieved in fewer than thirteen steps. The beta-carboline motif was efficiently constructed through a Pictet-Spengler reaction with alpha-cyanotryptamine, followed by the removal of the cyano group and autoxidation (aromatization). Furthermore, bioinspired reactions were developed to provide different alkaloid skeletons.
Article
Chemistry, Medicinal
Jukiya Sakamoto, Mariko Kitajima, Hayato Ishikawa
Summary: In this study, the total syntheses of several alkaloids from Mitragyna speciosa were successfully achieved using organocatalytic reactions and bioinspired transformations. These alkaloids exhibit potent biological activity with analgesic properties.
CHEMICAL & PHARMACEUTICAL BULLETIN
(2022)
Article
Chemistry, Medicinal
Nanako Nakashima, Jukiya Sakamoto, Kenta Rakumitsu, Mariko Kitajima, Lia Dewi Juliawaty, Hayato Ishikawa
Summary: A new pentacyclic monoterpenoid indole alkaloid glycoside named secorubenine (1) was isolated from the heartwood of Adina rubescens collected in Indonesia. Its structure was elucidated through spectroscopic analysis and chemical modification, followed by a bioinspired enantioselective total synthesis achieved in 12 steps. The structure and absolute stereochemistry of the compound were confirmed during synthesis.
CHEMICAL & PHARMACEUTICAL BULLETIN
(2022)
