Mechanistic Switch in Dual Gold Catalysis of Diynes: C(sp³)–H Activation through Bifurcation—Vinylidene versus Carbene Pathways

The other side of the mountain: Changing the framework of diyne systems opens up new cyclization modes for dual gold catalysis. Instead of a 5-endo cyclization and gold vinylidenes a 6-endo cyclization gives rise to gold-stabilized carbenes as key intermediates for selective C-H insertions.