Research news, Nov. 1st, 2013.
Coordination-Induced Skeletal Rearrangements of Zirconacyclobutene-Silacyclobutene Fused Complexes
Jing Zhao, Shaoguang Zhang, Wen-Xiong Zhang, and Zhenfeng Xi*
Coord. Chem. Rev. 2013, DOI: http://dx.doi.org/doi:10.1016/j.ccr.2013.08.032
Coordination-induced skeletal rearrangement of transition-metal complexes is of fundamental interest both synthetically and mechanistically. Besides commonly observed ligand substitution, the coordination of ligands may greatly alter the steric and electronic environment around the metal center, thus activating the whole compound, resulting in novel rearrangement or cleavage of chemical bonds. Subsequent formations of chemical bonds would lead to synthetically useful methods for new transition-metal complexes and organic compounds. Zirconacycles have been proved to be very useful for synthetic organic and organometallic chemistry. The present review concentrates on the coordination-induced skeletal rearrangement of zirconacyclobutene-silacyclobutene fused complexes. When treated with nitriles, alkynes, ketones, or other unsaturated organic molecules, the zirconacyclobutene-silacyclobutene fused complexes underwent the coordination-induced rearrangement and new chemical bond forming process, other than the expected direct insertion reactions. Different types of rearrangements were observed depending on the coordinating unsaturated organic molecules. A variety of zirconacycles and organic products were formed efficiently from the zirconacyclobutene-silacyclobutene fused complexes and the unsaturated organic molecules through the coordination-induced rearrangement and new chemical bond forming process.