Catalytic oxidations using ruthenium porphyrins - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 37

(Figure 15) 151 . The more bulky benzyl- D -glycal was not oxidized under the
heterogeneous conditions.
Further developments in supported Ru-porphyrin catalysts include
attachment to a polymer through a covalent linkage 152 . Ruthenium
complexes with the unsymmetrical 5,10,15-tris(4-R-phenyl)-20-(4-hydroxy-

phenyl)porphyrins (R = Cl, Me) (abbreviated, for example,
have been attached through the hydroxy group to Merrifield's
peptide resin (MPR) bearing benzyl chloride groups according to Figure 16.
The resulting catalysts and

(4-MPR)TPP)CO epoxidized a variety of alkenes with as oxidant,
the chloro system giving higher yields (56-98%) with Ru (8.6 wt.%.) :
oxidant: substrate = 1 : 1400 : 1000, in benzene, at r. t. for 24 h. Cis -stilbene
and norbornene yield exclusively cis -epoxides. In contrast, with the M-41( m )
system, the polymer oxidized trans -stilbene and
to the corresponding trans epoxides in 90 and 86 %
yields, respectively. Several alkenes were oxidized catalytically for the first
time with high selectivity: 3,4-dihydronaphthalene yielded 62% epoxide,