Synthesis and Evaluation of Sterically Demanding Ruthenium Dithiolate Catalysts for Stereoretentive Olefin Metathesis

Dithiolate ligands
have recently been used in ruthenium-catalyzed
olefin metathesis and have provided access to a kinetically E selective pathway through stereoretentive olefin metathesis.
The typical dithiolate used is relatively simple with low steric demands
imparted on the catalyst. We have developed a synthetic route that
allows access to sterically demanding dithiolate ligands. The catalysts
generated provided a pathway to study the intricate structure–activity
relationships in olefin metathesis. It was found that DFT calculations
can predict the ligand arrangement around the ruthenium center with
remarkable accuracy. These dithiolate catalysts proved resistant to
ligand isomerization and were stable even under forcing conditions.
Additionally, catalyst initiation and olefin metathesis studies delivered
a better understanding to the interplay between dithiolate ligand
structure and catalyst activity and selectivity.