Substitution vs. addition. Regioselective electro-bromination of benzofuran

Hideo Tanaka; Yusuke Kawakami; Manabu Kuroboshi; Sigeru Torii

doi:10.3987/COM-00-S(I)78

Substitution vs. addition. Regioselective electro-bromination of benzofuran

Hideo Tanaka, Yusuke Kawakami, Manabu Kuroboshi, Sigeru Torii

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

4 Citations (Scopus)

Abstract

Regioselective electro-bromination of benzofuran (2) was achieved successfully by an adequate choice of solvents and bromide salts to afford 5-bromobenzofuran (1), 5,7-dibromobenzofuran (3), and 2,3-dibromo-2,3-dihydrobenzofuran (4), respectively. Upon electrolysis of benzofuran (2) in AcOH/H₂O (100/1) containing NH₄Br, substitution at the C(5)-position of benzofuran (2) proceeded smoothly to afford 5-bromobenzofuran (1). After passage of totally 4 F/mol of electricity in a similar medium, 5,7-dibromobenzofuran (3) was obtained as a sole product. On the other hand, electrolysis of benzofuran (2) in CH₂Cl₂/H₂O (1/1) and/or AcOH/H₂O (10/1) in the presence of either NaBr or NH₄Br afforded 2,3-dibromo-2,3-dihydrobenzofuran (4), exclusively.

Original language	English
Pages (from-to)	825-831
Number of pages	7
Journal	Heterocycles
Volume	54
Issue number	2
DOIs	https://doi.org/10.3987/COM-00-S(I)78
Publication status	Published - Feb 1 2001

Keywords

2,3-Dibromo-2,3-dihydrobenzofuran
5-Bromobenzofuran
Benzofuran
Bromination
Electrolysis

ASJC Scopus subject areas

Analytical Chemistry
Pharmacology
Organic Chemistry

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10.3987/COM-00-S(I)78

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title = "Substitution vs. addition. Regioselective electro-bromination of benzofuran",

abstract = "Regioselective electro-bromination of benzofuran (2) was achieved successfully by an adequate choice of solvents and bromide salts to afford 5-bromobenzofuran (1), 5,7-dibromobenzofuran (3), and 2,3-dibromo-2,3-dihydrobenzofuran (4), respectively. Upon electrolysis of benzofuran (2) in AcOH/H2O (100/1) containing NH4Br, substitution at the C(5)-position of benzofuran (2) proceeded smoothly to afford 5-bromobenzofuran (1). After passage of totally 4 F/mol of electricity in a similar medium, 5,7-dibromobenzofuran (3) was obtained as a sole product. On the other hand, electrolysis of benzofuran (2) in CH2Cl2/H2O (1/1) and/or AcOH/H2O (10/1) in the presence of either NaBr or NH4Br afforded 2,3-dibromo-2,3-dihydrobenzofuran (4), exclusively.",

keywords = "2,3-Dibromo-2,3-dihydrobenzofuran, 5-Bromobenzofuran, Benzofuran, Bromination, Electrolysis",

author = "Hideo Tanaka and Yusuke Kawakami and Manabu Kuroboshi and Sigeru Torii",

year = "2001",

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T1 - Substitution vs. addition. Regioselective electro-bromination of benzofuran

AU - Tanaka, Hideo

AU - Kawakami, Yusuke

AU - Kuroboshi, Manabu

AU - Torii, Sigeru

PY - 2001/2/1

Y1 - 2001/2/1

N2 - Regioselective electro-bromination of benzofuran (2) was achieved successfully by an adequate choice of solvents and bromide salts to afford 5-bromobenzofuran (1), 5,7-dibromobenzofuran (3), and 2,3-dibromo-2,3-dihydrobenzofuran (4), respectively. Upon electrolysis of benzofuran (2) in AcOH/H2O (100/1) containing NH4Br, substitution at the C(5)-position of benzofuran (2) proceeded smoothly to afford 5-bromobenzofuran (1). After passage of totally 4 F/mol of electricity in a similar medium, 5,7-dibromobenzofuran (3) was obtained as a sole product. On the other hand, electrolysis of benzofuran (2) in CH2Cl2/H2O (1/1) and/or AcOH/H2O (10/1) in the presence of either NaBr or NH4Br afforded 2,3-dibromo-2,3-dihydrobenzofuran (4), exclusively.

AB - Regioselective electro-bromination of benzofuran (2) was achieved successfully by an adequate choice of solvents and bromide salts to afford 5-bromobenzofuran (1), 5,7-dibromobenzofuran (3), and 2,3-dibromo-2,3-dihydrobenzofuran (4), respectively. Upon electrolysis of benzofuran (2) in AcOH/H2O (100/1) containing NH4Br, substitution at the C(5)-position of benzofuran (2) proceeded smoothly to afford 5-bromobenzofuran (1). After passage of totally 4 F/mol of electricity in a similar medium, 5,7-dibromobenzofuran (3) was obtained as a sole product. On the other hand, electrolysis of benzofuran (2) in CH2Cl2/H2O (1/1) and/or AcOH/H2O (10/1) in the presence of either NaBr or NH4Br afforded 2,3-dibromo-2,3-dihydrobenzofuran (4), exclusively.

KW - 2,3-Dibromo-2,3-dihydrobenzofuran

KW - 5-Bromobenzofuran

KW - Benzofuran

KW - Bromination

KW - Electrolysis

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Substitution vs. addition. Regioselective electro-bromination of benzofuran

Abstract

Keywords

ASJC Scopus subject areas

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