Table 2. Cyclotrimerization of Alkynes Using Catalyst 4.
Conditions: alkyne (3.0 mmol), 4 (2.5 mol %, 0.075 mmol), 5 mL of benzene, room temperature, and 3 h.
Isolated yield of a and b after column chromatography.
Determined by 1H NMR spectroscopy.
No reaction was observed, recovering the alkynes employed.