In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called An Opened Route to 1,3-Dimethylenecyclobutanes via Sequential Ruthenium-Catalyzed [2 + 2] Cycloaddition of Allenyl Boronate and Palladium Suzuki Coupling, published in 2005-08-24, which mentions a compound: 92390-26-6, Name is Chloro(1,5-cyclooctadiene)(pentamethylcyclopentadienyl)ruthenium, Molecular C18H28ClRu, Safety of Chloro(1,5-cyclooctadiene)(pentamethylcyclopentadienyl)ruthenium.
The regioselective head-to-head [2 + 2] cyclodimerization of allenyl boronate catalyzed by the ruthenium catalyst [Cp*RuCl(COD)] leads to a novel diboronated 1,3-dimethylenecyclobutane. Consecutive palladium-catalyzed C-C couplings open a route to novel disubstituted 1,3-dimethylenecyclobutane species. The X-ray crystalline structure of the phenyl-substituted 1,3-dimethylenecyclobutane is provided.
After consulting a lot of data, we found that this compound(92390-26-6)Safety of Chloro(1,5-cyclooctadiene)(pentamethylcyclopentadienyl)ruthenium can be used in many types of reactions. And in most cases, this compound has more advantages.
Reference:
Chapter 1 An introduction to palladium catalysis,
Palladium/carbon catalyst regeneration and mechanical application method