Pentacoordinate Ruthenium(II) Catecholthiolate and Mercaptophenolate Catalysts for Olefin Metathesis: Anionic Ligand Exchange and Ease of Initiation

The investigations disclosed offer insight regarding several key features of Ru-based catecholthiolate olefin metathesis catalysts. Factors influencing the facility with which the two anionic ligands undergo exchange and those that affect the rates of catalyst release are elucidated by examination of more than a dozen new complexes. These studies shed light on how different chelating groups can influence Ru–S bond strength and, as a result, the facility of catecholthiolate rotation. The trans influence series ether Z selectivity levels that are higher than those when the corresponding catecholate systems are used, but less so in comparison to catecholthiolate complexes. A rationale for variations in stereoselectivity is presented.