Asymmetric Ring-Closing Metathesis with a Twist


  • H.F.T.K. thanks the Deutsche Forschungsgemeinschaft (International Research Training Group Münster-Nagoya, GRK 1143, predoctoral fellowship, 2007–2009), and M.O. thanks the Aventis Foundation (Karl-Winnacker-Stipendium, 2006–2008).


A double flip! The catalyst shown, with a molybdenum stereocenter and monodentate ligands (Si=SitBuMe2), promotes asymmetric ring-closing metathesis of a broad range of substrates. Its unprecedented activity originates from its structural fluxionality, which enables double inversion at the metal center in the course of a single catalytic cycle. The catalyst passed the test in a metathesis reaction en route to (+)-quebrachamine (see scheme).

original image