Kagan oxidation

Kagan oxidations (a) Kagan, H.B. (2000) Asymmetric oxidation of sulfides, in Catalytic Asymmetric Synthesis, 2nd edn (ed. I. Ojima), John Wiley Sons, Inc., New York, pp. 327 (b) Pitchen, P.,... 

Significant improvements in asymmetric oxidations were made by Modena and, especially, by Kagan, and their coworkers. Both groups used chiral peroxotitanium complexes patterned after the Sharpless reagent as the oxidants. 

Of several procedures for the stereoselective oxidation of sulfides using organometallic complexes, two adaptations of Kagan s original process have gained prominence. In the first method the diol (36) is reacted with Ti(0 Pr)4 to form the catalyst. With cumyl hydroperoxide as the stoichiometric oxidant, methyl para-tolyl sulfide was converted into the optically active sulfoxide in 42 % yield (98 % ee)[109]. 

In the second noteworthy adaptation of the Kagan method, Reetz and coworkers utilized the dinitrooctahydronaphthol (37). Oxidation of methyl para-tolylsulfide under similar conditions to those in the above paragraph furnished the optically active sulfoxide (86% ee)[110]. 

The use of furylhydroperoxides[1] has facilitated an operationally simple procedure, alternative to the one reported by Kagan[2]. Oxidation takes place rapidly and very high e.e.s have been obtained, especially in the case of aryl methyl sulfides, while overoxidation to sulfone can be reduced to a great extent (<3 %) under the proposed experimental conditions. 

Shvedova AA, Kisin ER, Murray AR, Gorelik O, Arepalli S, Castranova V, Young SH, Gao F, Tyurina YY, Oury TD, Kagan VE (2007) Vitamin E deficiency enhances pulmonary inflammatory response and oxidative stress induced by single-walled carbon nanotubes in C57BL/6 mice. Toxicol Appl Pharm 221 339-348. 

N. V. Gorbunov, A. N. Osipov, B. W. Day, B. Zayas-Rivera, V. E. Kagan, N. M. Elsayed, Reduction of Ferrylmyoglobin and Ferrylhemoglobin by Nitric Oxide A Protective Mechanism against Ferryl Hemoprotein-Induced Oxidations , Biochemistry 1995, 34, 6689-6699. 

To characterize phospholipid oxidation during apoptosis, cellular phospholipids were metabolically labeled at sn-2 position with a natural unsaturated florescent fatty acid containing four conjugated double bonds, cw-parinaric acid (cw-PnA) (Kagan et al, 1998 Tyurina et al, 2001). Oxidative desttuction of any part of the conjugated double bond system of... 

Using this protocol we found that apoptosis induced by a number of different oxidants is associated with selective oxidation of specific phospholipid classes, most notably PS (Kagan et al, 2000, Tyurina et al,... 

Several cell lines were used to inveshgate the role of PS oxidahon in apoptosis. Preferenhal oxidahon of PS was observed in human leukemia HL-60 cells (Fabisiak et al, 1998, 2000 Kawai et al, 2000), and normal human keratinocytes (Shvedova et al, 2001). Similarly, in pheochromocytoma PC 12 cells exposed to a radical-generating anhneoplashc dmg, neocarzinostatin, extemalizahon of PS was potentiated by its selechve oxidation in whole cells (Schor et al, 1999). In contrast, this selechve PS oxidahon did not occur in liposomes prepared from mixtures of PnA-labeled phospholipids extracted from the ceUs and exposed to oxidants imder the same conditions (Fabisiak et al, 1998 Kagan et al, 2000 Shvedova et al,... 

Fabisiak, J.P., Kagan, V.E., Ritov, V.B., and Laso, J.S., 1997, Bcl-2 inhibits selective oxidation and externalization of phosphatidylseiine during paraquat-induced apoptosis, Am. J. Physiol. (CellPhysiol.) 212 C675-C684. 

Fabisiak, J.P., Tyurina, Y.Y., Tyuiin, V.A., Lazo, J.S., and Kagan, V.E., 1998, Random vresus selective membrane phosphohpid oxidation in apoptotis role ofphosphatidylserine, Biochemistry yi 13781-13790. 

Gorbunov, N. V., Tyurina, Y. Y., Salama, G., Day, B. W., Claycamp, H. G., Argyros, G., Elsayed, N. M., and Kagan, V. E., 1998, Nitric oxide protects cardiomyocytes against tert-butyl hydroperoxide-induced formation of alkoxyl and peroxyl radicals and peroxidation ofphosphatidylserine,S oc/ em. Biophys. Res. Commun. 244 647-651. 

Enantiomerically pure sulfoxides play an important role in asymmetric synthesis either as chiral building blocks or stereodirecting groups [156]. In the last years, metal- and enzyme-catalyzed asymmetric sulfoxidations have been developed for the preparation of optically active sulfoxides. Among the metal-catalyzed processes, the Kagan sulfoxidation [157] is the most efficient, in which the sulfide is enantioselectively oxidized by Ti(OzPr)4/tBuOOH in the presence of tartrate as chirality source. However, only alkyl aryl sulfides may be oxidized by this system in high enantiomeric excesses, and poor enantioselectivities were observed for dialkyl sulfides. 

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