Easily removable olefin metathesis catalysts

A small family of olefin metathesis catalysts bearing a polar quaternary ammonium group is described. The presence of this group allows for efficient separation of ruthenium impurities after the reaction. Application of catalysts 9 and 11 leads to organic products of high purity, which exhibit surprisingly low ruthenium contamination levels (usually below 5 ppm) after a simple and inexpensive purification step.