Selective formation of olefins using olefin metathesis

Olefin metathesis catalysts have become one of the tools for the efficient synthesis of complex mols. Until recently, the catalysts demonstrated poor catalyst controlled selectivity of the product double bond. Over the past several years, complexes based on molybdenum, tungsten and ruthenium have been discovered that will produce olefins good to excellent selectivity for the generation of Z olefins both in cross and in ring closing metathesis. New ligands have been developed that result in different selectivities and open new applications of metathesis in the synthesis of an array of complex mols. These catalysts are developed through design, computation and serendipity. Applications range from the prepn. of pharmaceuticals to the control of the structure of polymeric materials