The Experts below are selected from a list of 85992 Experts worldwide ranked by ideXlab platform
Tetsuaki Tanaka - One of the best experts on this subject based on the ideXlab platform.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
ChemInform, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:The synthesis proceeds via ketyl radical attack on the Aromatic Ring, single electron transfer, and nucleophilic attack of the resulting dienyl anion to the ester group.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
Tetrahedron Letters, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:We report a samarium(II)-mediated tandem spirocyclization reaction to provide dispiro[4.2.4.2]tetradecadiene and dispiro[4.2.5.2]pentadecadiene skeletons. The reaction was achieved by intramolecular addition of a ketyl radical onto an Aromatic Ring beaRing an electrophilic moiety followed by reductive capture of the spirohexadienyl radical intermediate with SmI2 in the presence of HMPA.
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samarium ii mediated spirocyclization by intramolecular aryl radical addition onto an Aromatic Ring
Journal of Organic Chemistry, 2008Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Hiroaki Ohno, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization by intramolecular addition of aryl radicals onto an Aromatic Ring was achieved by the reaction of N-(2-iodophenyl)-N-alkylbenzamides with SmI2 in the presence of HMPA, yielding spirocyclic indolin-2-one derivatives. The ether congeners afford spirocyclic benzofuran derivatives in moderate yields by aryl radical addition onto a benzene Ring without having an electron-withdrawing group. The reaction with other aryl groups such as naphthalene and indole Rings is also described.
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samarium ii promoted radical spirocyclization onto an Aromatic Ring
Journal of Organic Chemistry, 2003Co-Authors: Hiroaki Ohno, Mitsuaki Okumura, Ryutaro Wakayama, Hiroki Iwasaki, Shinichiro Maeda, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization onto an Aromatic Ring was achieved by the reaction of methyl 4-(4-oxoalkyl)benzoates with SmI2 in the presence of i-PrOH and HMPA, yielding methyl 1-alkyl-1-hydroxyspiro[4.5]dec-6-ene-8-carboxylates in moderate to high yields. Utilizing this chemistry, spiro[3.5] and -[5.5] systems, and sterically congested spiro[4.5] systems, were easily synthesized. For the successful conversion, appropriate activation of the Aromatic Ring has proven to be extremely important: while an ester or amide functionality on the Aromatic Ring can promote the spirocyclization, a sulfonamide substituent causes ortho cyclization.
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the first samarium ii mediated stereoselective spirocyclization onto an Aromatic Ring
Chemical Communications, 2002Co-Authors: Hiroaki Ohno, Mitsuaki Okumura, Ryutaro Wakayama, Shinichiro Maeda, Tetsuaki TanakaAbstract:The first samarium(II)-mediated spirocyclisation onto an Aromatic Ring was achieved by the reaction of methyl 4-(4-oxoalkyl)benzoates with SmI2 in the presence of i-PrOH and HMPA, yielding methyl 1-alkyl-1-hydroxyspiro[4.5]dec-6-ene-8-carboxylates in moderate to high yields.
Hiroaki Ohno - One of the best experts on this subject based on the ideXlab platform.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
ChemInform, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:The synthesis proceeds via ketyl radical attack on the Aromatic Ring, single electron transfer, and nucleophilic attack of the resulting dienyl anion to the ester group.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
Tetrahedron Letters, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:We report a samarium(II)-mediated tandem spirocyclization reaction to provide dispiro[4.2.4.2]tetradecadiene and dispiro[4.2.5.2]pentadecadiene skeletons. The reaction was achieved by intramolecular addition of a ketyl radical onto an Aromatic Ring beaRing an electrophilic moiety followed by reductive capture of the spirohexadienyl radical intermediate with SmI2 in the presence of HMPA.
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samarium ii mediated spirocyclization by intramolecular aryl radical addition onto an Aromatic Ring
Journal of Organic Chemistry, 2008Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Hiroaki Ohno, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization by intramolecular addition of aryl radicals onto an Aromatic Ring was achieved by the reaction of N-(2-iodophenyl)-N-alkylbenzamides with SmI2 in the presence of HMPA, yielding spirocyclic indolin-2-one derivatives. The ether congeners afford spirocyclic benzofuran derivatives in moderate yields by aryl radical addition onto a benzene Ring without having an electron-withdrawing group. The reaction with other aryl groups such as naphthalene and indole Rings is also described.
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samarium ii promoted radical spirocyclization onto an Aromatic Ring
Journal of Organic Chemistry, 2003Co-Authors: Hiroaki Ohno, Mitsuaki Okumura, Ryutaro Wakayama, Hiroki Iwasaki, Shinichiro Maeda, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization onto an Aromatic Ring was achieved by the reaction of methyl 4-(4-oxoalkyl)benzoates with SmI2 in the presence of i-PrOH and HMPA, yielding methyl 1-alkyl-1-hydroxyspiro[4.5]dec-6-ene-8-carboxylates in moderate to high yields. Utilizing this chemistry, spiro[3.5] and -[5.5] systems, and sterically congested spiro[4.5] systems, were easily synthesized. For the successful conversion, appropriate activation of the Aromatic Ring has proven to be extremely important: while an ester or amide functionality on the Aromatic Ring can promote the spirocyclization, a sulfonamide substituent causes ortho cyclization.
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the first samarium ii mediated stereoselective spirocyclization onto an Aromatic Ring
Chemical Communications, 2002Co-Authors: Hiroaki Ohno, Mitsuaki Okumura, Ryutaro Wakayama, Shinichiro Maeda, Tetsuaki TanakaAbstract:The first samarium(II)-mediated spirocyclisation onto an Aromatic Ring was achieved by the reaction of methyl 4-(4-oxoalkyl)benzoates with SmI2 in the presence of i-PrOH and HMPA, yielding methyl 1-alkyl-1-hydroxyspiro[4.5]dec-6-ene-8-carboxylates in moderate to high yields.
Hiroki Iwasaki - One of the best experts on this subject based on the ideXlab platform.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
ChemInform, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:The synthesis proceeds via ketyl radical attack on the Aromatic Ring, single electron transfer, and nucleophilic attack of the resulting dienyl anion to the ester group.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
Tetrahedron Letters, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:We report a samarium(II)-mediated tandem spirocyclization reaction to provide dispiro[4.2.4.2]tetradecadiene and dispiro[4.2.5.2]pentadecadiene skeletons. The reaction was achieved by intramolecular addition of a ketyl radical onto an Aromatic Ring beaRing an electrophilic moiety followed by reductive capture of the spirohexadienyl radical intermediate with SmI2 in the presence of HMPA.
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samarium ii mediated spirocyclization by intramolecular aryl radical addition onto an Aromatic Ring
Journal of Organic Chemistry, 2008Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Hiroaki Ohno, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization by intramolecular addition of aryl radicals onto an Aromatic Ring was achieved by the reaction of N-(2-iodophenyl)-N-alkylbenzamides with SmI2 in the presence of HMPA, yielding spirocyclic indolin-2-one derivatives. The ether congeners afford spirocyclic benzofuran derivatives in moderate yields by aryl radical addition onto a benzene Ring without having an electron-withdrawing group. The reaction with other aryl groups such as naphthalene and indole Rings is also described.
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samarium ii promoted radical spirocyclization onto an Aromatic Ring
Journal of Organic Chemistry, 2003Co-Authors: Hiroaki Ohno, Mitsuaki Okumura, Ryutaro Wakayama, Hiroki Iwasaki, Shinichiro Maeda, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization onto an Aromatic Ring was achieved by the reaction of methyl 4-(4-oxoalkyl)benzoates with SmI2 in the presence of i-PrOH and HMPA, yielding methyl 1-alkyl-1-hydroxyspiro[4.5]dec-6-ene-8-carboxylates in moderate to high yields. Utilizing this chemistry, spiro[3.5] and -[5.5] systems, and sterically congested spiro[4.5] systems, were easily synthesized. For the successful conversion, appropriate activation of the Aromatic Ring has proven to be extremely important: while an ester or amide functionality on the Aromatic Ring can promote the spirocyclization, a sulfonamide substituent causes ortho cyclization.
Yoshiki Chujo - One of the best experts on this subject based on the ideXlab platform.
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Construction of Aromatic-Ring-layered structures using a terphenylene-layered polymer as the scaffold
Polymer Chemistry, 2013Co-Authors: Yuichi Tsuji, Yasuhiro Morisaki, Yoshiki ChujoAbstract:A series of Aromatic-Ring-layered polymers were synthesized by the polymer reaction using a terphenylene-layered polymer as a scaffold. FT-IR spectra of the resulting polymers revealed that Aromatic Rings were quantitatively introduced into the terphenylene-layered polymer backbone. UV-vis absorption spectra exhibited intramolecular interactions among the layered Aromatic Rings within a single polymer chain. Excimer emission from the layered Aromatic units was observed in the fluorescence spectra of the polymers, even in dilute solution, suggesting intramolecular interactions among the Aromatic units in the excited state. This polymer reaction method was shown to be a convenient method to align various Aromatic Rings one-dimensionally in a single polymer chain.
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Synthesis of Aromatic-Ring-Layered Polymers
Optoelectronics - Materials and Techniques, 2011Co-Authors: Yasuhiro Morisaki, Yoshiki ChujoAbstract:In the fields of polymer and material chemistry, conjugated polymers (Skotheim et al., 2006) are an important class of polymers for next-generation optoelectronic materials due to their intriguing conductivity, photoluminescence, electroluminescence, and liquid crystallinity. Numerous conjugated polymers have been synthesized thus far, and a variety of unique conjugation systems have been incorporated into conjugated polymer backbones. One of the current research topics in this field focuses on the construction of layered and/or π-stacked structures. Layered π-electron systems are commonly found in both nature and artificial materials; for example, light-harvesting antenna complexes in photosynthetic systems, such as chlorophylls and bacteriochlorophylls, consist of layered π-electron systems. In optoelectronic materials, charges are delocalized in some layers and transferred from one electrode to the opposite one through the layered π-electron systems. Despite the importance of the layered structures of the π-electron systems, the synthesis of polymers comprising layered-Aromatic Rings and π-electron systems in a single polymer chain has rarely been studied (Morisaki & Chujo, 2006; Morisaki & Chujo, 2008a; Morisaki & Chujo, 2009d; Nakano, 2010). To achieve the construction of the desired layered structure, xanthene, anthracene, and naphthalene compounds can be employed as scaffolds. The rotary motion of two Aromatic units substituted at the 4,5-positions of xanthene, 1,8-positions of anthracene, and 1,8positions of naphthalene is restricted due to steric hindrance, leading to a face-to-face structure. Thus, this review presents a summary of the syntheses and properties of a new class of Aromatic Ring-layered polymers, as well as oligomers containing xanthene, anthracene, and naphthalene scaffolds. Due to the vast number of studies on xanthene-, anthracene-, and naphthalene-based face-to-face dimeric systems, the polymers and oligomers (i.e., three or more face-to-face Aromatic Rings) are drawn.
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Aromatic-Ring-layered polymers composed of fluorene and xanthene
Polymer Journal, 2011Co-Authors: Jonas Alves Fernandes, Yasuhiro Morisaki, Yoshiki ChujoAbstract:Aromatic-Ring-layered polymers were synthesized by Sonogashira–Hagihara coupling reaction using xanthene as a scaffold. The polymers were characterized by various spectroscopic and electrochemical methods. The polymers emit brightly without excimer formation, despite the layered structure.
Toru Eguchi - One of the best experts on this subject based on the ideXlab platform.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
ChemInform, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:The synthesis proceeds via ketyl radical attack on the Aromatic Ring, single electron transfer, and nucleophilic attack of the resulting dienyl anion to the ester group.
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a novel samarium ii mediated tandem spirocyclization onto an Aromatic Ring
Tetrahedron Letters, 2011Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Masayuki Yamashita, Hiroaki Ohno, Tetsuaki TanakaAbstract:We report a samarium(II)-mediated tandem spirocyclization reaction to provide dispiro[4.2.4.2]tetradecadiene and dispiro[4.2.5.2]pentadecadiene skeletons. The reaction was achieved by intramolecular addition of a ketyl radical onto an Aromatic Ring beaRing an electrophilic moiety followed by reductive capture of the spirohexadienyl radical intermediate with SmI2 in the presence of HMPA.
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samarium ii mediated spirocyclization by intramolecular aryl radical addition onto an Aromatic Ring
Journal of Organic Chemistry, 2008Co-Authors: Hiroki Iwasaki, Toru Eguchi, Nozomi Tsutsui, Hiroaki Ohno, Tetsuaki TanakaAbstract:Samarium(II)-mediated spirocyclization by intramolecular addition of aryl radicals onto an Aromatic Ring was achieved by the reaction of N-(2-iodophenyl)-N-alkylbenzamides with SmI2 in the presence of HMPA, yielding spirocyclic indolin-2-one derivatives. The ether congeners afford spirocyclic benzofuran derivatives in moderate yields by aryl radical addition onto a benzene Ring without having an electron-withdrawing group. The reaction with other aryl groups such as naphthalene and indole Rings is also described.