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In an Attempt to Provide a User's Guide to the Galaxy of Benzylidene, Alkoxybenzylidene, and Indenylidene Ruthenium Olefin Metathesis Catalysts
Author(s) -
Bieniek Michał,
Michrowska Anna,
Usanov Dmitry L.,
Grela Karol
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701340
Subject(s) - catalysis , steric effects , ruthenium , metathesis , olefin metathesis , salt metathesis reaction , chemistry , combinatorial chemistry , olefin fiber , organic chemistry , polymerization , polymer
The data reported in this paper demonstrate that great care must be taken when choosing an appropriate catalyst for a given metathesis reaction. First‐generation catalysts were found to be useful in the metathesis of sterically unhindered substrates. Second‐generation catalysts (under optimised conditions) showed good to excellent activities toward sterically hindered and electron‐withdrawing group (EWG)‐substituted alkenes that do not react using the first‐generation complexes. A strong temperature effect was noted on all of the reactions tested. Interestingly, attempts to force a reaction by increasing the catalyst loading were much less effective. Therefore, when possible, it is suggested that metathesis transformations should be carried out with a second‐generation catalyst at 70 °C in toluene. However, different second‐generation catalysts proved to be optimal for different applications and no single catalyst outperformed all others in all cases. Nevertheless, some empirical rules can be deduced from the model experiments, providing preliminary hints for the selection of the optimal catalysts.