Figure 2.

Cycloaddition reactions by Mack et al. A: Ni‐pellet catalyzed cycloaddition of alkyne derivatives leading to a mixture of cyclooctatetraene and benzene derivatives.6 B: Copper and silver‐catalyzed [2+1] cycloaddition. A competing reaction was set up to test the selectivity of the used metals.8b C: In situ generation and cycloaddition of an azide compound.8c