CpRuCl(PPh3)(2)/MeI catalyst system for the [2+2] cycloaddition of norbornenes with disubstituted alkynes

CpRu(PPh3)(2)I generated in situ by mixing CpRu(PPh3)(2)Cl and methyl iodide catalyzed the [2+2] cycloaddition of norbornene (or norbomadiene) and disubtituted alkynes to afford functionalized cyclobutenes.