Selectivity switch in the synthesis of vinylgold(I) intermediates
An unexpected regioselectivity reversal was observed in the synthesis of vinylgold(I) complexes from propargyl carboxamides. The use of [Au(IPr)(OH)] affords preferentially vinylgold(I) complexes resulting from a 5-exo-dig cyclization, whereas the use [Au(IPr)]+ species, generated in situ starting f...
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| Main Authors: | , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
October 28, 2011
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| In: |
Organometallics
Year: 2011, Volume: 30, Issue: 22, Pages: 6328-6337 |
| ISSN: | 1520-6041 |
| DOI: | 10.1021/om2009556 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1021/om2009556
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| Author Notes: | A. Stephen K. Hashmi, Andreas M. Schuster, Sylvain Gaillard, Luigi Cavallo, Albert Poater, and Steven P. Nolan |
| Summary: | An unexpected regioselectivity reversal was observed in the synthesis of vinylgold(I) complexes from propargyl carboxamides. The use of [Au(IPr)(OH)] affords preferentially vinylgold(I) complexes resulting from a 5-exo-dig cyclization, whereas the use [Au(IPr)]+ species, generated in situ starting from [Au(IPr)(Cl)] and AgOTf, leads to vinylgold(I) complexes which form via a 6-endo-dig cyclization, This unexpected “selectivity switch” for this cyclization led us to propose two different reaction pathways enabling the formation of the two different products. One mechanism involves the [Au(IPr)]+ species with “classical” π activation of the alkyne framework of the carboxamides, and the second represents an “unusual” use of the basic Brønsted character of [Au(IPr)(OH)]. Mechanistic and DFT studies support the mechanistic hypotheses. |
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| Item Description: | Gesehen am 07.09.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1520-6041 |
| DOI: | 10.1021/om2009556 |