Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes

Ken Ichiro Imamura; Eiji Yoshikawa; Vladimir Gevorgyan; Tomoko Sudo; Naoki Asao; Yoshinori Yamamoto

doi:10.1139/v01-134

Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes

Ken Ichiro Imamura, Eiji Yoshikawa, Vladimir Gevorgyan, Tomoko Sudo, Naoki Asao, Yoshinori Yamamoto

Research output: Contribution to journal › Article › peer-review

19 Scopus citations

Abstract

The EtAlCl₂-mediated intramolecular addition of silyl enol ethers to both terminal and internal unactivated alkynes, bearing alkyl and phenyl susbstituents at the alkyne moiety, gave mono- and bicyclic β,γ-unsaturated ketones in good to excellent yields. On the other hand, the silyloxy-substituted cyclic vinylsilanes were obtained in moderate to high yields when the reactions were catalyzed by B(C₆F₅)₃ in the presence of triethylsilane. All the reactions proceeded via endo-fashion exclusively. The mechanisms of these regiospecific Lewis acid-assisted carbocyclizations are proposed.

Original language	English (US)
Pages (from-to)	1624-1631
Number of pages	8
Journal	Canadian Journal of Chemistry
Volume	79
Issue number	11
DOIs	https://doi.org/10.1139/v01-134
State	Published - Jan 1 2001
Externally published	Yes

Keywords

Alkynes
Carbocyclization
Lewis acid
Silyl enol ethers

ASJC Scopus subject areas

Catalysis
Chemistry(all)
Organic Chemistry

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title = "Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes",

abstract = "The EtAlCl2-mediated intramolecular addition of silyl enol ethers to both terminal and internal unactivated alkynes, bearing alkyl and phenyl susbstituents at the alkyne moiety, gave mono- and bicyclic β,γ-unsaturated ketones in good to excellent yields. On the other hand, the silyloxy-substituted cyclic vinylsilanes were obtained in moderate to high yields when the reactions were catalyzed by B(C6F5)3 in the presence of triethylsilane. All the reactions proceeded via endo-fashion exclusively. The mechanisms of these regiospecific Lewis acid-assisted carbocyclizations are proposed.",

keywords = "Alkynes, Carbocyclization, Lewis acid, Silyl enol ethers",

author = "Imamura, {Ken Ichiro} and Eiji Yoshikawa and Vladimir Gevorgyan and Tomoko Sudo and Naoki Asao and Yoshinori Yamamoto",

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TY - JOUR

T1 - Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes

AU - Imamura, Ken Ichiro

AU - Yoshikawa, Eiji

AU - Gevorgyan, Vladimir

AU - Sudo, Tomoko

AU - Asao, Naoki

AU - Yamamoto, Yoshinori

PY - 2001/1/1

Y1 - 2001/1/1

N2 - The EtAlCl2-mediated intramolecular addition of silyl enol ethers to both terminal and internal unactivated alkynes, bearing alkyl and phenyl susbstituents at the alkyne moiety, gave mono- and bicyclic β,γ-unsaturated ketones in good to excellent yields. On the other hand, the silyloxy-substituted cyclic vinylsilanes were obtained in moderate to high yields when the reactions were catalyzed by B(C6F5)3 in the presence of triethylsilane. All the reactions proceeded via endo-fashion exclusively. The mechanisms of these regiospecific Lewis acid-assisted carbocyclizations are proposed.

AB - The EtAlCl2-mediated intramolecular addition of silyl enol ethers to both terminal and internal unactivated alkynes, bearing alkyl and phenyl susbstituents at the alkyne moiety, gave mono- and bicyclic β,γ-unsaturated ketones in good to excellent yields. On the other hand, the silyloxy-substituted cyclic vinylsilanes were obtained in moderate to high yields when the reactions were catalyzed by B(C6F5)3 in the presence of triethylsilane. All the reactions proceeded via endo-fashion exclusively. The mechanisms of these regiospecific Lewis acid-assisted carbocyclizations are proposed.

KW - Alkynes

KW - Carbocyclization

KW - Lewis acid

KW - Silyl enol ethers

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JF - Canadian Journal of Chemistry

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Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes

Abstract

Keywords

ASJC Scopus subject areas

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