cs300151x_si_001.pdf (456 kB)
Active Ruthenium Catalysts Based on Phosphine-Modified Ru/CeO2 for the Selective Addition of Carboxylic Acids to Terminal Alkynes
journal contribution
posted on 2012-08-03, 00:00 authored by Masami Nishiumi, Hiroki Miura, Kenji Wada, Saburo Hosokawa, Masashi InoueThe modification of ruthenium species supported on ceria
in the presence of suitable phosphines
under H2 at 100 °C was found to generate catalytically
active Ru species that were effective for the regio- and stereoselective
addition of carboxylic acids to terminal alkynes. The reactions in
the presence of a catalytic amount of Ru/CeO2 modified
with 1,4-bis(diphenylphosphino)butane gave the anti-Markovnikov adducts
in high yields with excellent (Z)-isomer selectivities.
On the other hand, the reactions with the trioctylphosphine-modified
catalyst gave the Markovnikov adducts as major products. Among the
catalysts examined, only ceria- or zirconia-supported catalysts were
effective, and hot filtration tests using the phosphine-modified Ru/CeO2 catalyst suggested that soluble ruthenium species showed
quite a high catalytic activity. Very small amounts of ruthenium species
were detected in the solution. The solid Ru/CeO2 could
be repeatedly used as a reservoir of active catalysts without a significant
loss of activity.