Fig. 6: Mechanistic hypothesis.
From: Copper-catalyzed intermolecular formal (5 + 1) annulation of 1,5-diynes with 1,2,5-oxadiazoles

Plausible catalytic cycle.
From: Copper-catalyzed intermolecular formal (5 + 1) annulation of 1,5-diynes with 1,2,5-oxadiazoles
Plausible catalytic cycle.