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Dive into the research topics where Kunio Sugiyama is active.

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Featured researches published by Kunio Sugiyama.


Tetrahedron Letters | 1992

Photochemistry of o-methyl-substituted aromatic ketone with 5-isobutylidene-1,3-dioxane-4-,6-dione derivatives

Takashi Tsuno; Kunio Sugiyama

Abstract Photolyses of o -methylacetophenone or o -methylbenzophenone with 5-isobutylidene-1,3-dioxane-4,6-diones produced novel adducts, bonding between the β-carbon of the acylales and the o -methyl carbon of the aromatic ketones.


Tetrahedron | 2001

Allenyl(vinyl)methane photochemistry. Photochemistry of γ-(3-methyl-1-phenyl-1,2-butadienyl)-substituted α,β-unsaturated ester and nitrile derivatives

Takashi Tsuno; Hidetaka Hoshino; Rieko Okuda; Kunio Sugiyama

Abstract The direct photolyses of the γ-(3-methyl-1-phenyl-1,2-butadienyl)-substituted α,β-unsaturated esters and nitriles gave the bicyclo[2.1.0]pentanes, cross-conjugated trienes, and several intramolecular products, while the triplet-sensitization led to the former two compounds. It was found that the photochemoselectivity depended on the substituents on the vinyl group and would be controlled by the energy using the triplet sensitizers.


Heterocycles | 1994

Photochemistry of g-Allenyl-substituted Conjugated Alkylidenecycloalkanones

Kunio Sugiyama; Masato Yoshida; Takashi Tsuno

The photolyses of the γ-allenyl-substituted conjugated alkylidenecyclo- alkanones underwent the intramolecular oxa-Diels-Alder reaction and the E-Z geometrical isomerization, and for the cyclopentanone possessing a 3-methyl-1,2-butadienyl group, the intramolecular [2+2] cycloaddition also occurred. The oxa-Diels-Alder reaction takes place via photochemi- cal process of the Z-enones


Heterocycles | 1994

Addition reaction of photoenols from o-methyl-substituted aromatic ketones with 5-alkylidene-1,3-dioxane-4,6-dione derivatives

Kunio Sugiyama; Takashi Tsuno

Photolyses of 2-methylacetophenone or 2-methylbenzophenone with isobutylidene Meldrums acid or 5-isobutylidene-1,3-dioxane-4,6-dione derivatives produced novel adducts, bonding between the β-carbon of the acylals and the 2-methyl carbon of the aromatic ketones. However, the photoenol derived from benzocyclobutenols by thermolysis did not undergo the addition reaction with the acylal. The benzocyclobutenols reacted with isobutenylketene derived by pyrolysis of isobutylidene Meldrums acid to yield corresponding benzocyclobutenyl 4-methyl-3-pentenoate derivatives


Tetrahedron | 2002

Allenyl(vinyl)methane photochemistry. Photochemistry of γ-allenyl-substituted α,β-unsaturated enone derivatives

Takashi Tsuno; Masato Yoshida; Tetsu Iwata; Kunio Sugiyama

Abstract The photolyses of the γ-allenyl-substituted alkylidenecycloalkanones underwent mainly E – Z geometric isomerization; several enones gave pyrans by the photochemical intramolecular oxa-Diels–Alder reaction and bicyclo[2.1.0]pentanes by the intramolecular [2+2] cycloaddition. The photolyses of the γ-(3-methyl-1,2-butadienyl)-substituted 3-alkylidenepenta-2,4-diones led to bicyclo[2.1.0]pentane, while the γ-(1,2-propadienyl-substituted) 3-alkylidenepenta-2,4-diones underwent intramolecular [2+2] cycloaddition and intramolecular oxa-Diels–Alder reaction.


Tetrahedron Letters | 1997

Allenyl(vinyl)methane photochemistry. Photochemistry of 4,4,7-trimethyl-5-phenyl-2,5,6-octatrienate derivatives

Takashi Tsuno; Hidetaka Hoshino; Kunio Sugiyama

Abstract The direct photolysis of the diester in the title compounds gave a cross conjugated triene, [2+2] cycloadduct, pyran, and cyclopropene. The direct photolysis of the monoester afforded a cross conjugated triene, [2+2] cycloadduct, cyclopropene, and its Z -form. The sensitized photolysis of these esters afforded the trienes and [2+2] cycloadducts, which were derived from the triplet excited state of the different chromophores.


Heterocycles | 1991

Diels-Alder reaction of photoenol of 2-methylbenzaldehyde with 5-alkylidene-1,3-dioxane-4,6-dione derivatives

Kunio Sugiyama; Takashi Tsuno

Spiro- and polyspirocyclic compounds containing the 1,2,3,4-tetrahydro-1-naphthol structure were obtained by the Diels-Alder reaction of the photoenol of 2-methylbenzaldehyde with 5-alkylidene-1,3-dioxane-4,6-dione derivatives. The cycloaddition proceeded regio- and stereoselectively. However, in the case using 5-benzylidene-2,2-dimethyl-1,3-dioxane-4,6-dione and diethyl isobutylidenemalonate, the cycloaddition failed


Heterocycles | 1990

Epoxidation of 5-Alkylidene and 5-Benzylidene Substituted 1,3-Dioxane-4,6-dione Derivatives by Hydrogen Peroxide without Catalyst

Kunio Sugiyama; Takashi Tsuno

5-Alkylidene and 5-benzylidene substituted 1,3-dioxane-4,6-dione derivatives readily reacted with hydrogen peroxide at room temperature without any catalyst to give the corresponding spiro- and polyspirocyclic compounds containing oxirane ring in good yields


Journal of The Chemical Society-perkin Transactions 1 | 2000

Photochemical reactions of N-acylbenzoxazole-2-thiones

Takehiko Nishio; Ikuo Iida; Kunio Sugiyama

The photochemical reactions of N-acylbenzoxazole-2-thiones 1 are examined. Irradiation of N-acylbenzoxazole-2-thiones 1 in the presence of a variety of alkenes 2 yields 2-substituted benzoxazoles 3–20 and/or the unexpected products, iminothietanes 21–29 by intramolecular trapping of the acyl group by thiolate anion of the zwitterionic intermediate I and by the phenolate anion of the zwitterionic intermediate II, respectively, derived from the spirocyclic aminothietanes AT which are formed by regioselective [2+2] cycloaddition of the carbon–sulfur double bond of 1 to the alkene double bond.


Bulletin of the Chemical Society of Japan | 1995

Allenyl(vinyl)methane Photochemistry. Photochemistry of 5-[2-(1,2-Propadienyl)-Substituted Alkylidene]-2,2-dimethyl-1,3-dioxane-4,6-diones

Takashi Tsuno; Kunio Sugiyama

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Takashi Tsuno

College of Industrial Technology

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Hidetaka Hoshino

College of Industrial Technology

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Kosuke Kondo

College of Industrial Technology

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Rieko Okuda

College of Industrial Technology

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