A Simple and Effective Co-Catalyst for Ring-Closing Enyne Metathesis Using Grubbs I type Catalysts: A Practical Alternative to “Mori's Conditions”

摘要

“Catch-and-release”: Simple alk-1-enes are effective at liberating buta-1,3-dienes from vinyl alkylidene ruthenium complexes, as well as undergoing alkene–alkylidene exchange with enyne substrates to regenerate the alk-1-ene. This ability to “catch-and-release” ruthenium alkylidenes allows alk-1-enes higher than ethylene (“Mori's conditions”) to be used as a co-catalysts in terminal enyne metathesis with the Grubbs generation I complex (L=PCy3).