2-Lithio-3-methoxy-1,3-dimethylcyclopentene

A synthetic equivalent of 2-lithio-1,3-dimethylcyclopentadiene and useful synthon for 6-alkyl-1,4- dimethylfulvenes and ansa-metallocene complexes

Young Chul Won, Ui Gab Joung, Eun Sook Cho, Bun Yeoul Lee, Hyosun Lee, Young Whan Park, Kwang Ho Song

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

2-Bromo-3-methoxy-1,3-dimethylcyclopentene (3). is synthesized in 85% yield in 80 g scale by 1,2-addition of MeLi to 2-bromo-3-methyl-2-cyclopenten-1-one and subsequent in situ treatment of MeI. Addition of n-BuLi to the bromo-compound 3 in Et2O affords 2-lithio-3-methoxy-1,3- dimethylcyclopentene (1). Successive addition of RCHO [R = CH3, (CH2)2CH3, CH(CH3)2, C(CH3)3, H] and MeI to the lithium compound and aqueous acidic work-up provide cyclopentadiene compounds, 2-[CHR(OMe)]-1,3-Me 2C5H3 in 60-84% yields. Treatment of the cyclopentadienes with NaH or KH in pentane affords 1,4,6-trimethylfulvene, 6-n-propyl-1,4-dimethylfulvene, 6-isopropyl-1,4-dimethylfulvene, 6-tert-butyl-1,4-dimethylfulvene and 1,4-dimethylfulvenein 67-83% yields. Ligand for an ansa-metallocene complex, CH2C(1,3-Me2Cp) 2ZrCl2, can be shortly afforded in 64% yield by reacting the lithium compound 1 with the newly synthesized 1,4-dimethylfulvene.

Original languageEnglish
Pages (from-to)1052-1056
Number of pages5
JournalSynthesis
Issue number7
Publication statusPublished - 2004 May 6

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Lithium Compounds
Lithium compounds
Cyclopentanes
Ligands
metallocene

Keywords

  • Cyclopentadienes
  • Fulvene synthesis
  • Lithiation
  • Metallocenes
  • Organometallic reagents

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

2-Lithio-3-methoxy-1,3-dimethylcyclopentene : A synthetic equivalent of 2-lithio-1,3-dimethylcyclopentadiene and useful synthon for 6-alkyl-1,4- dimethylfulvenes and ansa-metallocene complexes. / Won, Young Chul; Joung, Ui Gab; Cho, Eun Sook; Lee, Bun Yeoul; Lee, Hyosun; Park, Young Whan; Song, Kwang Ho.

In: Synthesis, No. 7, 06.05.2004, p. 1052-1056.

Research output: Contribution to journalArticle

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title = "2-Lithio-3-methoxy-1,3-dimethylcyclopentene: A synthetic equivalent of 2-lithio-1,3-dimethylcyclopentadiene and useful synthon for 6-alkyl-1,4- dimethylfulvenes and ansa-metallocene complexes",
abstract = "2-Bromo-3-methoxy-1,3-dimethylcyclopentene (3). is synthesized in 85{\%} yield in 80 g scale by 1,2-addition of MeLi to 2-bromo-3-methyl-2-cyclopenten-1-one and subsequent in situ treatment of MeI. Addition of n-BuLi to the bromo-compound 3 in Et2O affords 2-lithio-3-methoxy-1,3- dimethylcyclopentene (1). Successive addition of RCHO [R = CH3, (CH2)2CH3, CH(CH3)2, C(CH3)3, H] and MeI to the lithium compound and aqueous acidic work-up provide cyclopentadiene compounds, 2-[CHR(OMe)]-1,3-Me 2C5H3 in 60-84{\%} yields. Treatment of the cyclopentadienes with NaH or KH in pentane affords 1,4,6-trimethylfulvene, 6-n-propyl-1,4-dimethylfulvene, 6-isopropyl-1,4-dimethylfulvene, 6-tert-butyl-1,4-dimethylfulvene and 1,4-dimethylfulvenein 67-83{\%} yields. Ligand for an ansa-metallocene complex, CH2C(1,3-Me2Cp) 2ZrCl2, can be shortly afforded in 64{\%} yield by reacting the lithium compound 1 with the newly synthesized 1,4-dimethylfulvene.",
keywords = "Cyclopentadienes, Fulvene synthesis, Lithiation, Metallocenes, Organometallic reagents",
author = "Won, {Young Chul} and Joung, {Ui Gab} and Cho, {Eun Sook} and Lee, {Bun Yeoul} and Hyosun Lee and Park, {Young Whan} and Song, {Kwang Ho}",
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T1 - 2-Lithio-3-methoxy-1,3-dimethylcyclopentene

T2 - A synthetic equivalent of 2-lithio-1,3-dimethylcyclopentadiene and useful synthon for 6-alkyl-1,4- dimethylfulvenes and ansa-metallocene complexes

AU - Won, Young Chul

AU - Joung, Ui Gab

AU - Cho, Eun Sook

AU - Lee, Bun Yeoul

AU - Lee, Hyosun

AU - Park, Young Whan

AU - Song, Kwang Ho

PY - 2004/5/6

Y1 - 2004/5/6

N2 - 2-Bromo-3-methoxy-1,3-dimethylcyclopentene (3). is synthesized in 85% yield in 80 g scale by 1,2-addition of MeLi to 2-bromo-3-methyl-2-cyclopenten-1-one and subsequent in situ treatment of MeI. Addition of n-BuLi to the bromo-compound 3 in Et2O affords 2-lithio-3-methoxy-1,3- dimethylcyclopentene (1). Successive addition of RCHO [R = CH3, (CH2)2CH3, CH(CH3)2, C(CH3)3, H] and MeI to the lithium compound and aqueous acidic work-up provide cyclopentadiene compounds, 2-[CHR(OMe)]-1,3-Me 2C5H3 in 60-84% yields. Treatment of the cyclopentadienes with NaH or KH in pentane affords 1,4,6-trimethylfulvene, 6-n-propyl-1,4-dimethylfulvene, 6-isopropyl-1,4-dimethylfulvene, 6-tert-butyl-1,4-dimethylfulvene and 1,4-dimethylfulvenein 67-83% yields. Ligand for an ansa-metallocene complex, CH2C(1,3-Me2Cp) 2ZrCl2, can be shortly afforded in 64% yield by reacting the lithium compound 1 with the newly synthesized 1,4-dimethylfulvene.

AB - 2-Bromo-3-methoxy-1,3-dimethylcyclopentene (3). is synthesized in 85% yield in 80 g scale by 1,2-addition of MeLi to 2-bromo-3-methyl-2-cyclopenten-1-one and subsequent in situ treatment of MeI. Addition of n-BuLi to the bromo-compound 3 in Et2O affords 2-lithio-3-methoxy-1,3- dimethylcyclopentene (1). Successive addition of RCHO [R = CH3, (CH2)2CH3, CH(CH3)2, C(CH3)3, H] and MeI to the lithium compound and aqueous acidic work-up provide cyclopentadiene compounds, 2-[CHR(OMe)]-1,3-Me 2C5H3 in 60-84% yields. Treatment of the cyclopentadienes with NaH or KH in pentane affords 1,4,6-trimethylfulvene, 6-n-propyl-1,4-dimethylfulvene, 6-isopropyl-1,4-dimethylfulvene, 6-tert-butyl-1,4-dimethylfulvene and 1,4-dimethylfulvenein 67-83% yields. Ligand for an ansa-metallocene complex, CH2C(1,3-Me2Cp) 2ZrCl2, can be shortly afforded in 64% yield by reacting the lithium compound 1 with the newly synthesized 1,4-dimethylfulvene.

KW - Cyclopentadienes

KW - Fulvene synthesis

KW - Lithiation

KW - Metallocenes

KW - Organometallic reagents

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