Cyclisation versus 1,1-carboboration: reactions of B(C6F5)3 with propargyl amides

A series of propargyl amides were prepared and their reactions with the Lewis acidic compound B(C6F5)3 were investigated. These reactions were shown to afford novel heterocycles under mild conditions. The reaction of a variety of N-substituted propargyl amides with B(C6F5)3 led to an intramolecular...

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Main Authors: Melen, Rebecca L. (Author) , Hansmann, Max M. (Author) , Lough, Alan J. (Author) , Hashmi, A. Stephen K. (Author) , Stephan, Douglas W. (Author)
Format: Article (Journal)
Language:English
Published: 06 August 2013
In: Chemistry - a European journal
Year: 2013, Volume: 19, Issue: 36, Pages: 11928-11938
ISSN:1521-3765
DOI:https://doi.org/10.1002/chem.201301899
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/https://doi.org/10.1002/chem.201301899
Verlag, lizenzpflichtig, Volltext: https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.201301899
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Author Notes:Rebecca L. Melen, Max M. Hansmann, Alan J. Lough, A. Stephen K. Hashmi, and Douglas W. Stephan
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Summary:A series of propargyl amides were prepared and their reactions with the Lewis acidic compound B(C6F5)3 were investigated. These reactions were shown to afford novel heterocycles under mild conditions. The reaction of a variety of N-substituted propargyl amides with B(C6F5)3 led to an intramolecular oxo-boration cyclisation reaction, which afforded the 5-alkylidene-4,5-dihydrooxazolium borate species. Secondary propargyl amides gave oxazoles in B(C6F5)3 mediated (catalytic) cyclisation reactions. In the special case of disubstitution adjacent to the nitrogen atom, 1,1-carboboration is favoured as a result of the increased steric hindrance (1,3-allylic strain) in the 5-alkylidene-4,5-dihydrooxazolium borate species.
Item Description:Im Titel sind die Zahlen "6", "5" und "3" tiefgestellt
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Physical Description:Online Resource
ISSN:1521-3765
DOI:https://doi.org/10.1002/chem.201301899