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, C-H, or N-H activation may occur. In the case of pyridones, the first three predominated with N-protected derivatives, whereas substrates containing N-H bonds followed an N-H 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.

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