Thermal Addition of Disilacyclobutenes and Acetylene

A Theoretical Study on Diels-Alder Type Reactions

Kazunari Yoshizawa, Song Yun Kang, Tokio Yamabe, Akinobu Naka, Mitsuo Ishikawa

研究成果: ジャーナルへの寄稿記事

10 引用 (Scopus)

抄録

The reaction pathways for the thermal additions of disilacyclobutenes and acetylene are discussed from B3LYP density-functional-theory computations. Butadiene is more stable in energy than cyclobutene, the corresponding ring compound, whereas disilabutadiene is less stable than disilacyclobutene. From detailed analyses of the potential energy surfaces, disilabutadienes formed by thermal ring opening of disilacyclobutenes are confirmed to play a central role in the addition reactions as intermediates in a manner similar to the Diels-Alder reaction. The activation energies for the symmetry-allowed conrotatory ring opening of 1,2-disilacyclobut-3-ene, 1,1,2,2-tetramethyl-1,2-disilacyclobut-3-ene, and 3,4-benzo-1,1,2,2-tetramethyl-1,2-disilacyclobutene are 41.5, 46.7, and 61.9 kcal/mol, respectively, and the activation energies for the Diels-Alder coupling reactions with acetylene are 1-4 kcal/mol when measured from the disilabutadiene intermediates at the B3LYP/6-31G** level of theory. Therefore the ring opening should be the rate-determining step in these reactions; once the four-membered ring of disilacyclobutene is opened by heat treatment, the addition reactions should readily take place, leading to six-membered ring products. The transition state for the addition of 1,4-disila-1,3-butadiene and acetylene is symmetrical with respect to the Si-C bonds being formed, whereas those of 1,1,4,4-tetramethyl-1,4-disila-1,3-butadiene and acetylene and of 1,2-bis(dimethylsilylene)cyclohexa-3,5-diene and acetylene are not symmetrical. There are good reasons that such asymmetrical transition states occur in these Diels-Alder reactions; one is the asymmetrical frontier orbitals in the methyl-substituted disilabutadienes, and the other is just a steric effect of the methyl groups.

元の言語英語
ページ(範囲)4637-4645
ページ数9
ジャーナルOrganometallics
18
発行部数22
DOI
出版物ステータス出版済み - 10 25 1999
外部発表Yes

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Acetylene
acetylene
rings
butadiene
Addition reactions
Diels-Alder reactions
Activation energy
Potential energy surfaces
activation energy
Density functional theory
dienes
Heat treatment
Hot Temperature
heat treatment
potential energy
density functional theory
orbitals
symmetry
1,3-butadiene
products

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

これを引用

Thermal Addition of Disilacyclobutenes and Acetylene : A Theoretical Study on Diels-Alder Type Reactions. / Yoshizawa, Kazunari; Kang, Song Yun; Yamabe, Tokio; Naka, Akinobu; Ishikawa, Mitsuo.

:: Organometallics, 巻 18, 番号 22, 25.10.1999, p. 4637-4645.

研究成果: ジャーナルへの寄稿記事

Yoshizawa, Kazunari ; Kang, Song Yun ; Yamabe, Tokio ; Naka, Akinobu ; Ishikawa, Mitsuo. / Thermal Addition of Disilacyclobutenes and Acetylene : A Theoretical Study on Diels-Alder Type Reactions. :: Organometallics. 1999 ; 巻 18, 番号 22. pp. 4637-4645.
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title = "Thermal Addition of Disilacyclobutenes and Acetylene: A Theoretical Study on Diels-Alder Type Reactions",
abstract = "The reaction pathways for the thermal additions of disilacyclobutenes and acetylene are discussed from B3LYP density-functional-theory computations. Butadiene is more stable in energy than cyclobutene, the corresponding ring compound, whereas disilabutadiene is less stable than disilacyclobutene. From detailed analyses of the potential energy surfaces, disilabutadienes formed by thermal ring opening of disilacyclobutenes are confirmed to play a central role in the addition reactions as intermediates in a manner similar to the Diels-Alder reaction. The activation energies for the symmetry-allowed conrotatory ring opening of 1,2-disilacyclobut-3-ene, 1,1,2,2-tetramethyl-1,2-disilacyclobut-3-ene, and 3,4-benzo-1,1,2,2-tetramethyl-1,2-disilacyclobutene are 41.5, 46.7, and 61.9 kcal/mol, respectively, and the activation energies for the Diels-Alder coupling reactions with acetylene are 1-4 kcal/mol when measured from the disilabutadiene intermediates at the B3LYP/6-31G** level of theory. Therefore the ring opening should be the rate-determining step in these reactions; once the four-membered ring of disilacyclobutene is opened by heat treatment, the addition reactions should readily take place, leading to six-membered ring products. The transition state for the addition of 1,4-disila-1,3-butadiene and acetylene is symmetrical with respect to the Si-C bonds being formed, whereas those of 1,1,4,4-tetramethyl-1,4-disila-1,3-butadiene and acetylene and of 1,2-bis(dimethylsilylene)cyclohexa-3,5-diene and acetylene are not symmetrical. There are good reasons that such asymmetrical transition states occur in these Diels-Alder reactions; one is the asymmetrical frontier orbitals in the methyl-substituted disilabutadienes, and the other is just a steric effect of the methyl groups.",
author = "Kazunari Yoshizawa and Kang, {Song Yun} and Tokio Yamabe and Akinobu Naka and Mitsuo Ishikawa",
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T1 - Thermal Addition of Disilacyclobutenes and Acetylene

T2 - A Theoretical Study on Diels-Alder Type Reactions

AU - Yoshizawa, Kazunari

AU - Kang, Song Yun

AU - Yamabe, Tokio

AU - Naka, Akinobu

AU - Ishikawa, Mitsuo

PY - 1999/10/25

Y1 - 1999/10/25

N2 - The reaction pathways for the thermal additions of disilacyclobutenes and acetylene are discussed from B3LYP density-functional-theory computations. Butadiene is more stable in energy than cyclobutene, the corresponding ring compound, whereas disilabutadiene is less stable than disilacyclobutene. From detailed analyses of the potential energy surfaces, disilabutadienes formed by thermal ring opening of disilacyclobutenes are confirmed to play a central role in the addition reactions as intermediates in a manner similar to the Diels-Alder reaction. The activation energies for the symmetry-allowed conrotatory ring opening of 1,2-disilacyclobut-3-ene, 1,1,2,2-tetramethyl-1,2-disilacyclobut-3-ene, and 3,4-benzo-1,1,2,2-tetramethyl-1,2-disilacyclobutene are 41.5, 46.7, and 61.9 kcal/mol, respectively, and the activation energies for the Diels-Alder coupling reactions with acetylene are 1-4 kcal/mol when measured from the disilabutadiene intermediates at the B3LYP/6-31G** level of theory. Therefore the ring opening should be the rate-determining step in these reactions; once the four-membered ring of disilacyclobutene is opened by heat treatment, the addition reactions should readily take place, leading to six-membered ring products. The transition state for the addition of 1,4-disila-1,3-butadiene and acetylene is symmetrical with respect to the Si-C bonds being formed, whereas those of 1,1,4,4-tetramethyl-1,4-disila-1,3-butadiene and acetylene and of 1,2-bis(dimethylsilylene)cyclohexa-3,5-diene and acetylene are not symmetrical. There are good reasons that such asymmetrical transition states occur in these Diels-Alder reactions; one is the asymmetrical frontier orbitals in the methyl-substituted disilabutadienes, and the other is just a steric effect of the methyl groups.

AB - The reaction pathways for the thermal additions of disilacyclobutenes and acetylene are discussed from B3LYP density-functional-theory computations. Butadiene is more stable in energy than cyclobutene, the corresponding ring compound, whereas disilabutadiene is less stable than disilacyclobutene. From detailed analyses of the potential energy surfaces, disilabutadienes formed by thermal ring opening of disilacyclobutenes are confirmed to play a central role in the addition reactions as intermediates in a manner similar to the Diels-Alder reaction. The activation energies for the symmetry-allowed conrotatory ring opening of 1,2-disilacyclobut-3-ene, 1,1,2,2-tetramethyl-1,2-disilacyclobut-3-ene, and 3,4-benzo-1,1,2,2-tetramethyl-1,2-disilacyclobutene are 41.5, 46.7, and 61.9 kcal/mol, respectively, and the activation energies for the Diels-Alder coupling reactions with acetylene are 1-4 kcal/mol when measured from the disilabutadiene intermediates at the B3LYP/6-31G** level of theory. Therefore the ring opening should be the rate-determining step in these reactions; once the four-membered ring of disilacyclobutene is opened by heat treatment, the addition reactions should readily take place, leading to six-membered ring products. The transition state for the addition of 1,4-disila-1,3-butadiene and acetylene is symmetrical with respect to the Si-C bonds being formed, whereas those of 1,1,4,4-tetramethyl-1,4-disila-1,3-butadiene and acetylene and of 1,2-bis(dimethylsilylene)cyclohexa-3,5-diene and acetylene are not symmetrical. There are good reasons that such asymmetrical transition states occur in these Diels-Alder reactions; one is the asymmetrical frontier orbitals in the methyl-substituted disilabutadienes, and the other is just a steric effect of the methyl groups.

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