Horseradish epoxidation

Ozaki S-I, Ortiz de Montellano PR (1995) Molecular engineering of horseradish peroxidase thioether sulfoxidation and styrene epoxidation by Phe-41 leucine and threonine mutants. J Am Chem Soc 117 7056-7064... 

The second type of oxygen transfer reaction is the epoxidation of olefins. This type of reaction is also rare in the plant cell biochemical factory, peroxidases of class III being inefficient catalysts. However, molecular engineered horseradish peroxidase is able to catalyze the... 

The results of recent investigations S of model systems provide compelling evidence that stabilized atomic oxygen is present in Compound I and Compound II of horseradish peroxidase. Thus, the combination of tetrakis(2,6-dichlorophenyl)-porphinato-iron(ni) perchlorate (6, Scheme 4-4) with pentafluoro-iodosobenzene, zn-chloroperbenzoic add, or ozone in acetonitrile at -35°C yields a green porphyrin-oxene adduct (7). This species, which has been characterized by spectroscopic, magnetic, and electrochemical methods, cleanly and stereospecifically epoxidizes olefins (>99% exo-norbornene-oxide). 

Nolte et al 46) produced an artificial enzyme based on the T4 replisome and applied it to the epoxidation of double bonds in synthetic polymers. Smith et al 51) reported that horseradish peroxidase catalyzes the oxidative polymerization of glucuronic acid. In recent literature, many biomimetic macromolecules with enzyme-like structures or functions have been reported including those that are dendrimers 64-66), those that have specified three-dimensional structures or recognition elements created by molecular imprinting 67), and other enzyme mimics 68). 

Intramolecular enantiosituselectivity is exemplified by the biosynthetic formation of the mustard oil glucoside sinigrin (60) in horseradish, " the deprotonation of N-Boc-pyrrolidine (62) with sec-butyllithium (s-BuLi)/(-)-sparteine, followed by methylation, "" and, the oxidation of enol 64. Intermolecular enantiosituselective transformations are exemplified by the hydrolysis of racemic N-dodecanoylphenylalanine p-nitrophenyl esters (( )-67) in the presence of tripeptide catalyst (Z)-L-Phe-L-His-L-Leu (68) in each of the latter two cases, only one (externally) enantiotopic carbonyl reacts preferentially. It should be pointed out parenthetically, that as a result of the enantiosituselectivity in these transformations, one has, in effect, kinetic resolution of ( )-67. The electron-impact induced elimination in acetate 71, and the oxidation of 73 exemplify intramolecular diastereosituselective transformations. The epoxidation of the mixture 76/77 is an example of an intermolecular diastereosituselective process at the same time that each substrate is subject to enantiositunonselectivity of the carbonyl sub-sites. 

Leurosine, the 15, 20 a-epoxide of (285), can be prepared by oxidation of 15, 20 -anhydrovinblastine (285) with hydrogen peroxide in the presence of either horseradish peroxidase or cell-free extracts of C roseus plants the evidence has been interpreted as indicating that leurosine is also a true natural product, not an artefact. ... 

EPOXIDATION AND SULFOXIDATION BY CYTOCHROME C PEROXIDASE AND HORSERADISH PEROXIDASE... 

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