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Published May 18, 2011 | Supplemental Material + Accepted Version
Journal Article Open

Highly Selective Ruthenium Metathesis Catalysts for Ethenolysis


N-Aryl,N-alkyl N-heterocyclic carbene (NHC) ruthenium metathesis catalysts are highly selective toward the ethenolysis of methyl oleate, giving selectivity as high as 95% for the kinetic ethenolysis products over the thermodynamic self-metathesis products. The examples described herein represent some of the most selective NHC-based ruthenium catalysts for ethenolysis reactions to date. Furthermore, many of these catalysts show unusual preference and stability toward propagation as a methylidene species and provide good yields and turnover numbers at relatively low catalyst loading (<500 ppm). A catalyst comparison showed that ruthenium complexes bearing sterically hindered NHC substituents afforded greater selectivity and stability and exhibited longer catalyst lifetime during reactions. Comparative analysis of the catalyst preference for kinetic versus thermodynamic product formation was achieved via evaluation of their steady-state conversion in the cross-metathesis reaction of terminal olefins. These results coincided with the observed ethenolysis selectivities, in which the more selective catalysts reach a steady state characterized by lower conversion to cross-metathesis products compared to less selective catalysts, which show higher conversion to cross-metathesis products.

Additional Information

© 2011 American Chemical Society. Received: January 21, 2011. Published: April 21, 2011. This research was supported by the National Science Foundation through a Graduate Research Fellowship to R.M.T. B. K. K. acknowledges the NDSEG for a graduate fellowship. The authors acknowledge Drs. Lawrence Henling and Michael Day for obtaining the X-ray crystallographic structures of complexes 12 and 15. We thank the NSF (CHE-1048404) and NIH (5R01GM031332-Z7) for funding and Materia, Inc. for the gift of methyl oleate and catalysts 1, 2, and 4.

Attached Files

Accepted Version - nihms291062.pdf

Supplemental Material - ja200246e_si_001.pdf

Supplemental Material - ja200246e_si_002.cif

Supplemental Material - ja200246e_si_003.cif


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