Shigeru Arai
Verified @chiba-u.jp
Gradate School of Pharmaceutical Sciences
Chiba University
RESEARCH INTERESTS
Organic Synthesis, Heterocyclic Chemisytry, Catalysis, Natural Products, Total Synthesis
88
Scopus Publications
Scopus Publications
- Isatogenols as Precursors for the Synthesis of Fully Substituted Indolines through Regio- and Stereoselective [3 + 2] Cycloaddition Using Various Olefins
Nanaka Ishihara, Shinji Harada, Masaya Nakajima, and Shigeru Arai
American Chemical Society (ACS)
Here, we describe a unique reactivity of isatogen derivatives bearing a hydroxy group at the C3-position (isatogenol) and their synthetic application to highly regio- and stereoselective [3 + 2] cycloaddition reactions. This method provides facile access to polyfused and highly functionalized heterocycles including consecutive stereocenters. Furthermore, DFT calculations revealed that hydrogen bonding is a key to controlling the regio- and stereoselectivity in the cycloaddition using acrylates. - Nickel-catalysed regio- and stereoselective hydrocyanation of alkynoates and its mechanistic insights proposed by DFT calculations
Shigeru Arai, Koichi Nakazawa, Xiao-Fei Yang, Masaya Nakajima, Shinji Harada, and Atsushi Nishida
Royal Society of Chemistry (RSC)
This work discloses the origin of regio- and stereoselectivity of hydrocyanation of alkynoates. - B(C<inf>6</inf>F<inf>5</inf>)<inf>3</inf>-catalyzed regio- and stereoselective cyanation of isatogens and their derivatives
Ryoka Sakai, Nanaka Ishihara, Shinji Harada, and Shigeru Arai
Elsevier BV - Construction of C2-C3 Contiguous Stereogenic Centers in Indoline Derivatives by 1,3-Dipolar Cycloaddition
Natsuki Ito, Shigeru Arai, and Atsushi Nishida
Wiley
AbstractWe report a reduction‐condensation‐1,3‐dipolar cycloaddition sequence to create C2‐C3 contiguous stereogenic centers in indoline derivatives. This method includes a one‐pot procedure starting from easily obtainable nitroketones and can be applied to intrarmolecular cycloaddition to give highly functionalized isoxazolidines. Both a length of methylene tether and olefinic substituents strongly affect the cycloaddition mode (exo/endo approach) to give highly stereo‐controlled tri‐ and tetracyclic systems through a single operation. Intermolecular cycloaddition is also applicable to the construction of 3 stereocenters in range of 47–87 % yield. - Synthesizing Chiral Hydrocarbazoles with a Tetrasubstituted Carbon Using Holmium-Catalyzed Enantioselective [4 + 2] Cycloaddition: Mechanistic Insights from Luminescence and DFT Studies
Shinji Harada, Shihori Sekino, Marisa Inaba, Ayumi Okita, Tetsuhiro Nemoto, Shigeru Arai, Hitomi Ohmagari, Miki Hasegawa, and Atsushi Nishida
American Chemical Society (ACS)
This study analyzes the feasibility of utilizing the catalytic and enantioselective [4 + 2] cycloaddition of sterically demanding heterocycle-incorporated siloxydienes to yield polycyclic skeletons with a tetrasubstituted carbon. A catalyst derived from lanthanide triflimide enabled the reaction. The mechanistic investigations and transformations of the adducts are also discussed. The proposed approach facilitates the synthesis of intricate polysubstituted skeletons, each with multiple contiguous chiral centers, thereby aiding in the production of diverse hydrocarbazoles for drug discovery purposes. - Photocatalytic Dearomative Intermolecular Seven-Membered Ring Construction of Benzofurans
Shinji Harada, Juntaro Yamamoto, Akito Okabe, and Shigeru Arai
Wiley
AbstractWe report the synthesis of seven‐membered carbocycles through the dearomative intermolecular reaction of benzofurans with vinylcyclopropanes. The significant feature of this method involves activating benzofurans through energy transfer from an activated photocatalyst. Substituent effects were investigated for each substrate, and hydrocyclohepta[b]benzofurans with a tetrasubstituted carbon were obtained as a single diastereomer. This synthetic approach compliments the reported methodologies for synthesizing this type of skeleton and introduces a new feedstock for this skeleton with a different substitution pattern. Computational studies of the reaction mechanism suggested that the reaction proceeds stepwise through addition, small ring opening, and re‐cyclization. This novel synthetic approach opens up new possibilities for efficiently constructing seven‐membered carbocycles. Moreover, it provides a valuable platform for discovering unique molecules with diverse substitution patterns. - Trichloromethylative Olefin Lactonization by Photoredox Catalysis
Shinji Harada, Ryotaro Koyama, Ryuya Masuda, and Shigeru Arai
Wiley
AbstractA trichloromethylative olefin lactonization reaction using an iridium photoredox catalyst was developed. The reactions proceeded at room temperature for olefins with various substituents and substitution patterns, and a variety of lactones with a tetrasubstituted carbon and trichloromethyl group were obtained regio‐ and stereoselectively. The reaction mechanism was elucidated through isotope labeling experiments. The chemical properties of the lactones containing the trichloromethyl groups were investigated, and synthetic transformations of the product were realized. - Regio-divergent nickel catalysis: intramolecular [4+2] and [2+2] cycloaddition reactions between vinylallenes and alkynes
Shigeru Arai, Saki Inagaki, Masaya Nakajima, and Atsushi Nishida
Royal Society of Chemistry (RSC)
Vinylallenes have been recognized as versatile C2 and C4 components for nickel-catalyzed intramolecular [4+2] and [2+2] cycloadditions. - Regio- and stereoselective synthesis of cyclobutanes by nickel-catalyzed homodimerizative [2 + 2] cycloaddition using allenamides
Yuna Kawata, Shigeru Arai, Masaya Nakajima, and Atsushi Nishida
Elsevier BV - Synthesis of nitrogen heterocycles through cyanative cyclization and cycloaddition reactions under transition metal catalysis
Shigeru Arai and Atsushi Nishida
The Japan Institute of Heterocyclic Chemistry - Cobalt-catalyzed hydrocyanation and hydroarylation of enamines
Shigeru Arai, Yuichi Sato, Natsuki Ito, and Atsushi Nishida
Elsevier BV - Regioselective [2+2+2] Cycloaddition Reaction Using Allene-ynes with Simple Allenes under Nickel Catalysis
Shigeru Arai, Arisa Izaki, Yuka Amako, Masaya Nakajima, Masanobu Uchiyama, and Atsushi Nishida
Wiley - Nickel-catalyzed [2 + 2] cycloaddition reaction using bisallenes
Shigeru Arai, Yuna Kawata, Yuka Amako, and Atsushi Nishida
Elsevier BV - Nickel-catalyzed regioselective hydrocyanation of terminal alkynes by assistance of a tosyl group
Shigeru Arai, Koichi Nakazawa, Xiao-fei Yang, and Atsushi Nishida
Elsevier BV - Cu-catalyzed regio- and stereoselective sulfonylation of multi-substituted allenes
S. Arai, Koki Matsumoto and A. Nishida
- Cobalt-catalyzed cyclization with the introduction of cyano, acyl and aminoalkyl groups
H. Hori, S. Arai and A. Nishida
An efficient synthesis of carbo- and heterocycles using C[double bond, length as m-dash]C, C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds under cobalt catalysis is described. The substituents on olefins are key for controlling the regio- and chemoselectivity in the initial hydrogen atom transfer step and quaternary carbons are efficiently constructed under mild conditions. Cyclopropane cleavage and tandem cyclization give highly functionalized bicyclic skeletons in a single operation. - Nickel-catalyzed hydrocyanation of allenes and its application
Shigeru Arai
Pharmaceutical Society of Japan
Cyano (CN) groups are equivalent to carbonyl as well as amino- and hydroxymethyl groups. Therefore, their catalytic introduction under metal catalysis is an important issue in synthetic organic chemistry. Ni-catalyzed hydrocyanation is one of the most well-investigated, powerful tools for installing a CN group. However, it is still difficult to control chemo- and regioselectivity. In this review, the author uses allenes to enable regio-, stereo-, and face-selective transformations to natural product synthesis and axial chirality transfer. - Nickel-catalyzed hydrocyanation of carbon-carbon multiple bonds and its application
Shigeru Arai, Yuka Amako, Hiroto Hori, and Atsushi Nishida
The Society of Synthetic Organic Chemistry, Japan - Formal synthesis of (±) —quebrachamine through regio- and stereoselective hydrocyanation of arylallene
Koki Matsumoto, Shigeru Arai, and Atsushi Nishida
Elsevier BV - Total synthesis of lundurines and related alkaloids
Shigeru Arai, Masaya Nakajima, and Atsushi Nishida
The Society of Synthetic Organic Chemistry, Japan - Olefin-Migrative Cleavage of Cyclopropane Rings through the Nickel-Catalyzed Hydrocyanation of Allenes and Alkenes
Hiroto Hori, Shigeru Arai, and Atsushi Nishida
Wiley
A nickel-catalyzed hydrocyanation triggered by hydronickelation of the carbon-carbon double bonds of allenes followed by cyclopropane cleavage is described. The observed regio- and stereochemistries in the products are strongly influenced by the initial hydronickelation step, and allenyl- and methylenecyclopropanes reacted smoothly to promote the cleavage of cyclopropane. In contrast, this cleavage was not observed with vinylidenecyclopropanes, because the initial hydronickelation does not give a suitable intermediate for cleavage of the cyclopropanes. - Total Synthesis of Lundurine and Related Alkaloids: Synthetic Approaches and Strategies
Shigeru Arai, Masaya Nakajima, and Atsushi Nishida
Elsevier - Transfer of axial chirality through the nickel-catalysed hydrocyanation of chiral allenes
Yuka Amako, Shigeru Arai, and Atsushi Nishida
Royal Society of Chemistry (RSC)
The transfer of axial chirality of allenes is beginning to be exploited as a powerful method for creating central chirality, particularly through the use of transition metal catalysis. - Furan-iminium cation cyclization (FIC) in a total synthesis of manzamine alkaloids
Kazuyuki Tokumaru, Toshiyuki Ohfusa, Shigeru Arai, and Atsushi Nishida
Springer Science and Business Media LLC - Total Syntheses of (+)-Grandilodine C and (+)-Lapidilectine B and Determination of their Absolute Stereochemistry
Masaya Nakajima, Shigeru Arai, and Atsushi Nishida
Wiley
Enantioselective total syntheses of the Kopsia alkaloids (+)-grandilodine C and (+)-lapidilectine B were accomplished. A key intermediate, spirodiketone, was synthesized in 3 steps and converted into the chiral enone by enantioselective deprotonation followed by oxidation with up to 76 % ee. Lactone formation was achieved through stereoselective vinylation followed by allylation and ozonolysis. The total synthesis of (+)-grandilodine C was achieved by palladium-catalyzed intramolecular allylic amination and ring-closing metathesis to give 8- and 5-membered heterocycles, respectively. Selective reduction of a lactam carbonyl gave (+)-lapidilectine B. The absolute stereochemistry of both natural products was thereby confirmed. These syntheses enable the scalable preparation of the above alkaloids for biological studies.