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Cobalt‐Mediated [2+2+2] Cycloaddition versus CH and NH Activation of Pyridones and Pyrazinones with Alkynes: An Experimental Study
Author(s) -
Aubert Corinne,
Betschmann Patrick,
Eichberg Michael J.,
Gandon Vincent,
Heckrodt Thilo J.,
Lehmann Jürg,
Malacria Max,
Masjost Birgit,
Paredes Elisa,
Vollhardt K. Peter C.,
Whitener Glenn D.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601823
Subject(s) - cycloaddition , reactivity (psychology) , chemistry , cobalt , medicinal chemistry , stereochemistry , catalysis , combinatorial chemistry , organic chemistry , medicine , alternative medicine , pathology
Abstract The reactivity of a range of pyridone and pyrazinone derivatives towards alkynes in the presence of cyclopentadienylcobaltbis(ethene) has been investigated. Depending on the nature of the substrates, [2+2+2]‐ or [2+2] cycloaddition, CH, or NH activation may occur. In the case of pyridones, the first three predominated with N‐protected derivatives, whereas substrates containing NH bonds followed an NH activation pathway. The [2+2+2] cycloaddition of an N ‐butynylisoquinolone was applied successfully to the total synthesis of anhydrolycorinone. Pyrazinone substrates showed similar patterns of reactivity.