Advanced fine-tuning of grubbs/hoveyda olefin metathesis catalysts: a further step toward an optimum balance between antinomic properties.
A 95% yield in the cross metathesis of acrylonitrile with a model olefin is achieved at 25 degrees C with only 3 mol % of the new air-stable ruthenium catalyst 1f shown in the enclosed structural diagram. Even more remarkable are the performances of its boosted version 1g incorporating an electron-withdrawing group. Both these new enhanced versions of Hoveyda catalyst are readily available from Grubbs second generation precatalyst upon reaction with a styrenyl ether the end group of which has been functionalized by an ester function. The latter acts as a weakly coordinating ligand allowing to reach a desirable balance between antinomic properties such as the catalyst's stability, a high activity for challenging substrates, and a high initiation rate.
Bieniek
Michał
M
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Bujok
Robert
R
Cabaj
Maciej
M
Lugan
Noël
N
Lavigne
Guy
G
Arlt
Dieter
D
Grela
Karol
K