Increased Efficiency in Cross-Metathesis Reactions of Sterically Hindered Olefins
Ian C. Stewart, Christopher J. Douglas and Robert H. Grubbs*
*The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, Email: rhgcaltech.edu
I. C. Stewart, C. J. Douglas, R. H. Grubbs, Org. Lett., 2008, 10, 441-444.
Steric bulk of N-heterocyclic carbene ligands affects the efficiency in cross-metathesis reactions. For the formation of disubstituted olefins containing one or more allylic substituents, the catalyst bearing N-tolyl groups is more efficient than the corresponding N-mesityl catalyst. In contrast, the formation of trisubstituted olefins is more efficient using the N-mesityl-containing catalyst.
see article for more examples