Ruthenium porphyrin catalyst

Caris-Veyrat, C. et al., Cleavage products of lycopene produced by in vitro oxidations characterization and mechanisms of formation, J. Agric. Food Chem., 51, 7318, 2003. Caris-Veyrat, C. et al., Mild oxidative cleavage of beta, beta-carotene by dioxygen induced by a ruthenium porphyrin catalyst characterization of products and of some possible intermediates, New J. Chem., 25, 203, 2001. 

Other examples involve the immobilization of ruthenium porphyrin catalysts [74]. While Severin et al. generated insoluble polymer-embedded catalysts 16 by co-polymerizing porphyrin derivatives with ethylene glycol dimethacrylate (EGD-MA) [74 a], Che et al. linked the ruthenium-porphyrin unit to soluble polyethylene glycol (PEG) 17 [74b]. Both immobilized catalysts were employed in a variety of olefin epoxidations with 2,6-dichloropyridine N-oxide (Gl2pyNO), providing similar conversions of up to 99% and high selectivities (Scheme 4.9). 

The decomposition of a-diazo esters by a ruthenium porphyrin catalyst has been used by Che and co-workers in a multicomponent strategy directed toward functionalized pyrrolidines 172. The first step involves the formation of a ruthenium... 

Deoxygenation of pyridine A-oxides has been achieved using dimethyldioxiran <95CC1831> and palladium with sodium hypophosphite <95GCI(124)385>. Pyridine A-oxides, with ruthenium porphyrin catalysts, have been used as an oxidant of aromatic compounds <95JA(117)8879> or olefins, alcohols, sulfides and alkanes <95FI(40)867>. 

The aziridination of olefins, which forms a three-membered nitrogen heterocycle, is one important nitrene transfer reaction. Aziridination shows an advantage over the more classic olefin hydroamination reaction in some syntheses because the three-membered ring that is formed can be further modified. More recently, intramolecular amidation and intermolecular amination of C-H bonds into new C-N bonds has been developed with various metal catalysts. When compared with conventional substitution or nucleophilic addition routes, the direct formation of C-N bonds from C-H bonds reduces the number of synthetic steps and improves overall efficiency.2 After early work on iron, manganese, and copper,6 Muller, Dauban, Dodd, Du Bois, and others developed different dirhodium carboxylate catalyst systems that catalyze C-N bond formation starting from nitrene precursors,7 while Che studied a ruthenium porphyrin catalyst system extensively.8 The rhodium and ruthenium systems are... 

A ruthenium porphyrin complex immobilized in a polymer can be used for catalytic epoxidation with 2,6-dichloropyridine N-oxide [112], Nitrous oxide (N2O) can be also used as oxidant for the epoxidation of trisubstituted olefins in the presence of ruthenium porphyrin catalyst [113], Asymmetric epoxidations have been reported using chiral ruthenium porphyrin complexes 35 [114], 36 [115], and 37 [116] (Eq. 3.62). 

Burii E, Severin K (2006) Molecular imprinting with ruthenium porphyrin catalysts. Chimia 60 182... 

J. L. Zhang, C. M. Che, Soluble polymer-supported ruthenium porphyrin catalysts for epoxidation, cyclopropanation, and aziridination of alkenes, Org. Lett. 4 (2002) 1911. 

O. Nestler, K. Severin, A ruthenium porphyrin catalyst immobilized in a highly cross-linked polymer, Org. Lett. 3 (2001) 3907. 

Groves, J. T. Quinn, R. Aerobic oxidation of olefins with ruthenium porphyrin catalysts. j. Am. Chem. Soc. 1985, 107, 5790-5792. 

In terms of miscellaneous reactions associated with aziridine synthesis, a ruthenium porphyrin catalyst was reported to facilitate a unique three-component coupling of nitroarenes with alkynes and a-diazo compounds to produce multifunctional aziridines (14OL1048). Pictured below is an intriguing palladium-catalyzed C-H bond activation/amination leading to the selective transformation of an aminolactone methyl group adjacent to an unprotected secondary amine into an aziridine (14NAT129). 

---