Gold-catalyzed cyclization of nonterminal propargylic amides to substituted alkylideneoxazolines and -oxazines
The substrate scope of the gold-catalyzed cyclization of nonterminal propargylic amides to oxazolines and oxazines was investigated. Sixteen alkyl-substituted and 35 aryl-substited substrates were prepared by a very variable route from trimethylsilyl-(TMS-)protected, nonterminal propargylamines. Ste...
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| Main Authors: | , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
22 June 2011
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| In: |
European journal of organic chemistry
Year: 2011, Issue: 24, Pages: 4595-4602 |
| ISSN: | 1099-0690 |
| DOI: | 10.1002/ejoc.201100342 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1002/ejoc.201100342 Verlag, lizenzpflichtig, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/ejoc.201100342 
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| Author Notes: | A. Stephen K. Hashmi, Andreas M. Schuster, Martin Schmuck, and Frank Rominger |
| Summary: | The substrate scope of the gold-catalyzed cyclization of nonterminal propargylic amides to oxazolines and oxazines was investigated. Sixteen alkyl-substituted and 35 aryl-substited substrates were prepared by a very variable route from trimethylsilyl-(TMS-)protected, nonterminal propargylamines. Steric and electronic influences of the substituents on product selectivity were studied. A chloromethyl substituent on the alkyne shows an efficient 1,4-elimination to deliver vinyloxazoles. A second alkynyl group, tethered to the alkyl group at the alkyne, in some cases led to a gold catalysis/Alder-ene domino reaction. With Barluenga's reagent the iodoalkylideneoxazoline can be formed in excellent yield. In contrast to the palladium-catalyzed protocols, the gold-catalyzed conditions for the cyclization of nonterminal propargylic amides are much milder, thus, for example, no special precautions are needed to prevent isomerization of the oxazolines to the aromatic oxazoles. |
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| Item Description: | Gesehen am 07.09.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1099-0690 |
| DOI: | 10.1002/ejoc.201100342 |