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Published February 15, 2006 | Supplemental Material + Accepted Version
Journal Article Open

Highly Active Chiral Ruthenium Catalysts for Asymmetric Ring-Closing Olefin Metathesis


The synthesis of olefin metathesis catalysts containing chiral, monodentate N-heterocyclic carbenes and their application to asymmetric ring-closing metathesis (ARCM) are reported. These catalysts retain the high levels of reactivity found in the related achiral variants (1a and 1b). Using the parent chiral catalysts 2a and 2b and derivatives that contain steric bulk in the meta positions of the N-bound aryl rings (catalysts 3−5), five- through seven-membered rings were formed in up to 92% ee. The addition of sodium iodide to catalysts 2a−4a (to form 2b−4b in situ) caused a dramatic increase in enantioselectivity for many substrates. Catalyst 5a, which gave high enantiomeric excesses for certain substrates without the addition of NaI, could be used in loadings of ≤1 mol %. Mechanistic explanations for the large sodium iodide effect as well as possible mechanistic pathways leading to the observed products are discussed.

Additional Information

© 2006 American Chemical Society. Received 31 August 2005. Published online 19 January 2006. Published in print 1 February 2006. We thank the NIH for financial support, Dr. Steven D. Goldberg and Angela Blum for helpful discussions, and Donde Anderson, Dr. Michael Day, and Larry Henling for the crystal structure of the Rh compound.

Attached Files

Accepted Version - nihms63197.pdf

Supplemental Material - ja055994dsi20050830_104735.cif

Supplemental Material - ja055994dsi20051121_084112.pdf


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