Electrophilc ipso-substltiitlon and some unique reaction behavior of 1,3,6-tri-tri-butylazulene

Taku Shoji; Shunji Ito; Tetsuo Okujima; Junya Higashi; Ryuji Yokoyama; Kozo Toyota; Masafumi Yasunami; Noboru Morita

doi:10.1002/ejoc.200801078

Electrophilc ipso-substltiitlon and some unique reaction behavior of 1,3,6-tri-tri-butylazulene

Taku Shoji, Shunji Ito, Tetsuo Okujima, Junya Higashi, Ryuji Yokoyama, Kozo Toyota, Masafumi Yasunami, Noboru Morita

SCI - Chemistry

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

28 Citations (Scopus)

Abstract

Electrophilic ipso-substitution reactions between 1,3,6-tritert- butylazulcne (2) and several electrophilic reagents were examined. Friedel-Crafts and Vilsmeier reactions of 2 gave the corresponding ipso-substitution products in moderate to excellent yields. One of the ipso-substitution products, 1,6- di-tert-butyl-3-formylazulene (5), was converted in high yield into the synthetically more useful azulene derivative 1,6-di-tert-butylazulene (1) by decarbonylation on treatment with pyrrole in acetic acid. Treatment of 2 with N-[(trifluoromelhyl)su]fonyl]pyridinium trifluoromethanesulfonate (TPT) unexpectedly afforded 1- trifluoromethylthioazulene 10 and l(8H)-azulenone 11. Compound 2 also reacted with tetracyanoethylene (TCNE) to give an excellent yield of cycloaddition product 13, rather than the ipso-substitution reaction product.

Original language	English
Pages (from-to)	1554-1563
Number of pages	10
Journal	European Journal of Organic Chemistry
Issue number	10
DOIs	https://doi.org/10.1002/ejoc.200801078
Publication status	Published - 2009 Apr

Keywords

Aromatic substitution
Azulenes
Cycloaddition
Electrochemistry
Ipso-Substitution

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Organic Chemistry

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10.1002/ejoc.200801078

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title = "Electrophilc ipso-substltiitlon and some unique reaction behavior of 1,3,6-tri-tri-butylazulene",

abstract = "Electrophilic ipso-substitution reactions between 1,3,6-tritert- butylazulcne (2) and several electrophilic reagents were examined. Friedel-Crafts and Vilsmeier reactions of 2 gave the corresponding ipso-substitution products in moderate to excellent yields. One of the ipso-substitution products, 1,6- di-tert-butyl-3-formylazulene (5), was converted in high yield into the synthetically more useful azulene derivative 1,6-di-tert-butylazulene (1) by decarbonylation on treatment with pyrrole in acetic acid. Treatment of 2 with N-[(trifluoromelhyl)su]fonyl]pyridinium trifluoromethanesulfonate (TPT) unexpectedly afforded 1- trifluoromethylthioazulene 10 and l(8H)-azulenone 11. Compound 2 also reacted with tetracyanoethylene (TCNE) to give an excellent yield of cycloaddition product 13, rather than the ipso-substitution reaction product.",

keywords = "Aromatic substitution, Azulenes, Cycloaddition, Electrochemistry, Ipso-Substitution",

author = "Taku Shoji and Shunji Ito and Tetsuo Okujima and Junya Higashi and Ryuji Yokoyama and Kozo Toyota and Masafumi Yasunami and Noboru Morita",

year = "2009",

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doi = "10.1002/ejoc.200801078",

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AU - Shoji, Taku

AU - Ito, Shunji

AU - Okujima, Tetsuo

AU - Higashi, Junya

AU - Yokoyama, Ryuji

AU - Toyota, Kozo

AU - Yasunami, Masafumi

AU - Morita, Noboru

PY - 2009/4

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N2 - Electrophilic ipso-substitution reactions between 1,3,6-tritert- butylazulcne (2) and several electrophilic reagents were examined. Friedel-Crafts and Vilsmeier reactions of 2 gave the corresponding ipso-substitution products in moderate to excellent yields. One of the ipso-substitution products, 1,6- di-tert-butyl-3-formylazulene (5), was converted in high yield into the synthetically more useful azulene derivative 1,6-di-tert-butylazulene (1) by decarbonylation on treatment with pyrrole in acetic acid. Treatment of 2 with N-[(trifluoromelhyl)su]fonyl]pyridinium trifluoromethanesulfonate (TPT) unexpectedly afforded 1- trifluoromethylthioazulene 10 and l(8H)-azulenone 11. Compound 2 also reacted with tetracyanoethylene (TCNE) to give an excellent yield of cycloaddition product 13, rather than the ipso-substitution reaction product.

AB - Electrophilic ipso-substitution reactions between 1,3,6-tritert- butylazulcne (2) and several electrophilic reagents were examined. Friedel-Crafts and Vilsmeier reactions of 2 gave the corresponding ipso-substitution products in moderate to excellent yields. One of the ipso-substitution products, 1,6- di-tert-butyl-3-formylazulene (5), was converted in high yield into the synthetically more useful azulene derivative 1,6-di-tert-butylazulene (1) by decarbonylation on treatment with pyrrole in acetic acid. Treatment of 2 with N-[(trifluoromelhyl)su]fonyl]pyridinium trifluoromethanesulfonate (TPT) unexpectedly afforded 1- trifluoromethylthioazulene 10 and l(8H)-azulenone 11. Compound 2 also reacted with tetracyanoethylene (TCNE) to give an excellent yield of cycloaddition product 13, rather than the ipso-substitution reaction product.

KW - Aromatic substitution

KW - Azulenes

KW - Cycloaddition

KW - Electrochemistry

KW - Ipso-Substitution

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Electrophilc ipso-substltiitlon and some unique reaction behavior of 1,3,6-tri-tri-butylazulene

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