The invention provides catalytically active compounds for alkyne metathesis comprising a ligand, on his part containing a guanidinate core which is forming a complex with a transition metal atom. Formally, the guanidinate core is a mononegative ligand that binds with the metal atom. One or both of the nitrogen atoms of the guanidiate core, which are not participating in the metal complexing bond, can be substituted with substituents being selected from hydrogen, alkyl, alkenyl, aromatic residues, optionally including hetero atoms, e.g. halogen atoms, preferably fluorine.
Preparation of Cyclophanes by Room-Temperature Ring-Closing Alkyne Metathesis with Imidazolin-2-iminato Tungsten Alkylidyne Complexes
作者:Stephan Beer、Kai Brandhorst、Jörg Grunenberg、Cristian G. Hrib、Peter G. Jones、Matthias Tamm
DOI:10.1021/ol800154y
日期:2008.3.1
Room-temperature ring-closing alkyne metathesis of 1,2-, 1,3-, and 1,4-bis(3-pentynyloxymethyl)benzenes has been investigated in the presence of catalytic amounts of an imidazolin-2-iminato tungsten alkylidyne complex. The m- and p-diynes selectively form the respective [10]metacyclophane or [10.10]paracyclophane, respectively, whereas a mixture of monomeric and dimeric cycloalkynes is obtained in