Altering the Cyclization Modes: Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures

Maloy Nayak, Young Kee Kang, Ikyon Kim

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]azepine-1-carbaldehydes along with the former products.

Original languageEnglish
Pages (from-to)1474-1477
Number of pages4
JournalOrganic Letters
Volume19
Issue number6
DOIs
Publication statusPublished - 2017 Mar 17

Fingerprint

Azepines
Cyclization
closures
Temperature
metathesis
rings
alkynes
pyrroles
products
Pyrroles
Alkynes
nitrogen
cations
acids
temperature
Cations
Nitrogen
Acids

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this

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title = "Altering the Cyclization Modes: Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures",
abstract = "In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]azepine-1-carbaldehydes along with the former products.",
author = "Maloy Nayak and Kang, {Young Kee} and Ikyon Kim",
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Altering the Cyclization Modes : Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures. / Nayak, Maloy; Kang, Young Kee; Kim, Ikyon.

In: Organic Letters, Vol. 19, No. 6, 17.03.2017, p. 1474-1477.

Research output: Contribution to journalArticle

TY - JOUR

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T2 - Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures

AU - Nayak, Maloy

AU - Kang, Young Kee

AU - Kim, Ikyon

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AB - In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]azepine-1-carbaldehydes along with the former products.

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