Palladium-Catalysed Syntheses of 3-Substituted Indoles and Hetero Analogues
(1996)- Abstract
- 3-Substituted indoles and their analogues - hetero condensed pyrroles (hetero-indoles) - have been synthesised by two different palladium-catalysed reactions:
a) A series of 2-silylated 3-substituted (hetero-)indoles have been prepared by palladium-catalysed coupling between o-iodo(het)arylamines and silyl substituted internal acetylenes. The outcome of the reaction was found to depend on the type of silyl substituent (tert-butyl dimethylsilyl or trimethylsilyl) employed. Tryptophan derivatives were obtained by desilylation of the corresponding 2-silylated indoles. Attempted desilylation of 2-silylated 3-hydroxymethyl-hetero-indoles resulted in a ring opening reaction of the pyrrole moiety.
b) A series... (More) - 3-Substituted indoles and their analogues - hetero condensed pyrroles (hetero-indoles) - have been synthesised by two different palladium-catalysed reactions:
a) A series of 2-silylated 3-substituted (hetero-)indoles have been prepared by palladium-catalysed coupling between o-iodo(het)arylamines and silyl substituted internal acetylenes. The outcome of the reaction was found to depend on the type of silyl substituent (tert-butyl dimethylsilyl or trimethylsilyl) employed. Tryptophan derivatives were obtained by desilylation of the corresponding 2-silylated indoles. Attempted desilylation of 2-silylated 3-hydroxymethyl-hetero-indoles resulted in a ring opening reaction of the pyrrole moiety.
b) A series of 3-substituted (hetero-)indoles have been prepared by N-allylation of N-(tert-butoxycarbonyl)-o-iodo(het)arylamines, followed by palladium-catalysed ring closure in a one pot reaction. (Hetero-)indole-3-acetic acid derivatives and (thia-)indole-3-pyruvic acid oxime ethers were thus obtained by employment of ethyl 4-bromocrotonate and the oxime ethers of ethyl (E)-2-oxo-5-bromo-3-pentenoate as N-allylating agents, respectively. Racemic thia-tryptophans were obtained by reduction of the oxime ether function in the corresponding thia-indole-3-pyruvic acid oxime ethers.
A novel method, involving treatment of the substrate with silica gel at low pressure, was discovered for the selective removal of N-BOC substituents (BOC=tert-butoxycarbonyl). (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/28663
- author
- Wensbo, David
- supervisor
- opponent
-
- Doc Andersson, Pehr, Uppsala University
- publishing date
- 1996
- type
- Thesis
- publication status
- published
- subject
- keywords
- Organic chemistry, Organisk kemi
- pages
- 58 pages
- publisher
- Organic Chemistry, Lund University
- defense location
- Chemical Center (G)
- defense date
- 1996-10-24 10:15:00
- external identifiers
-
- other:ISRN: LUNDL/NKOK-1034-SE
- language
- English
- LU publication?
- no
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Organic chemistry (S/LTH) (011001240)
- id
- 888f07be-2193-41ec-9ec4-bac4e6cc2a31 (old id 28663)
- date added to LUP
- 2016-04-04 10:22:04
- date last changed
- 2018-11-21 20:58:21
@phdthesis{888f07be-2193-41ec-9ec4-bac4e6cc2a31,
abstract = {{3-Substituted indoles and their analogues - hetero condensed pyrroles (hetero-indoles) - have been synthesised by two different palladium-catalysed reactions:<br/><br>
<br/><br>
a) A series of 2-silylated 3-substituted (hetero-)indoles have been prepared by palladium-catalysed coupling between o-iodo(het)arylamines and silyl substituted internal acetylenes. The outcome of the reaction was found to depend on the type of silyl substituent (tert-butyl dimethylsilyl or trimethylsilyl) employed. Tryptophan derivatives were obtained by desilylation of the corresponding 2-silylated indoles. Attempted desilylation of 2-silylated 3-hydroxymethyl-hetero-indoles resulted in a ring opening reaction of the pyrrole moiety.<br/><br>
<br/><br>
b) A series of 3-substituted (hetero-)indoles have been prepared by N-allylation of N-(tert-butoxycarbonyl)-o-iodo(het)arylamines, followed by palladium-catalysed ring closure in a one pot reaction. (Hetero-)indole-3-acetic acid derivatives and (thia-)indole-3-pyruvic acid oxime ethers were thus obtained by employment of ethyl 4-bromocrotonate and the oxime ethers of ethyl (E)-2-oxo-5-bromo-3-pentenoate as N-allylating agents, respectively. Racemic thia-tryptophans were obtained by reduction of the oxime ether function in the corresponding thia-indole-3-pyruvic acid oxime ethers.<br/><br>
<br/><br>
A novel method, involving treatment of the substrate with silica gel at low pressure, was discovered for the selective removal of N-BOC substituents (BOC=tert-butoxycarbonyl).}},
author = {{Wensbo, David}},
keywords = {{Organic chemistry; Organisk kemi}},
language = {{eng}},
publisher = {{Organic Chemistry, Lund University}},
title = {{Palladium-Catalysed Syntheses of 3-Substituted Indoles and Hetero Analogues}},
year = {{1996}},
}