Epoxidations with sodium hypochlorite

Ordinary alkenes (without an allylic OH group) have been enantioselectively epoxidized with sodium hypochlorite (commercial bleach) and an optically active manganese-complex catalyst. Variations of this oxidation use a manganese-salen complex with various oxidizing agents, in what is called the Jacobsen-Katsuki... 

Epoxidation with sodium hypochlorite.1 Ni(salen), is an effective catalyst for oxidation of some alkenes with NaOCl under phase-transfer conditions. Styrenes... 

W. Zhang, E. N. Jacobsen, Asymmetric olefin epoxidation with sodium hypochlorite catalyzed by easily prepared chiral manganese(III) salen complexes, /. Org. Chem. 56 (1991) 2296. 

This method has attracted little attention but was a key reaction used by Tishler and co-workers in a total synthesis of the antibiotic cerulenin (4), which contains a sensitive 4-keto-2,3-epoxy amide system. Thus the.butenolide 1 undergoes selective epoxidation with sodium hypochlorite in pyridine to give the hydroxy acid a, which lactonizes on warming to the epoxy lactone 2. Ammonolysis followed by oxidation with Collins reagent gives ( )-cerulenin (4). 

A convenient agent for the preparation of perfluoroalkene epoxides is sodium hypochlorite in a mixture with aqueous acetonitrile or another aprotic solvent cis-and tr<3 5-perfluoroalkenes are oxidized with retention of configuration [9, 10, 11, 12 13] (equation 7, Table 1)... 

Attempts have been made to exploit the intrinsic C2 symmetry of the phenolate-based dinickel core in enantioselective catalytic reactions. Therefore, enantiomerically pure C2-symmetric ligands such as (736a) and the corresponding dinickel systems (736b) have been prepared ( Equation (27)),1890 and (736b) was tested in the epoxidation of unfunctionalized alkenes with sodium hypochlorite as the oxidant. The catalytic reaction was found to be highly pH dependent with an optimum at a pH of 9. While the complex is catalytically active, significant enantioselectivity was not achieved. 

Interesting results were obtained in the asymmetric epoxidation of the (Z)-alkenes 94 using the (salen)Mn catalyst 95 in conjunction with sodium hypochlorite as an oxidant, giving the optically active -epoxides 96 as the major products,1711 as... 

The stepwise formation of epoxides through the reaction of alkenes with sodium hypochlorite with, or without, the isolation of the intermediate chlorohydrin has been subjected to catalysis with (V-benzylquininium chloride under liquiddiquid two-... 

Epoxidation of various acyclic and cyclic perfluorinated dienes is accomplished with an aqueous hypohalogenitc and acetonitrile as a cosolvent. The reactivity of a C = C bond toward this reagent is enhanced by the presence of the trifluoromethyl group. This activating effect is nicely illustrated by perfluoro(l-methylcyclohexa-l,4-diene), which reacts smoothly with sodium hypochlorite to give a diepoxide 11 in 58% yield,73 while the oxidation system failed for perfluorocyclohexadienes. Nonconjugated perfluorocyclohepta-1,4-diene (12) is oxidized to the corresponding diepoxide 13 by sodium hypobromite.74... 

The oxidations take place without affecting the sulfur atom when it is in one of its highest oxidation states (i.e., sulfur has an oxidation number of the value + 4 or +6, see Table 18). Thus, epoxidation of (pcntafluorosulfanyl)alkenes, e. g. 1, is achieved by treatment with sodium hypochlorite under phase transfer catalytic conditions.281... 

In this case, the O-benzyl quat hydroxide was used in conjunction with sodium hypochlorite in toluene [65]. Other reports of epoxidations of acyclic enones have appeared, showing 62% ee [66a] or lower enantioselectivity [24e,24h,48b,54a,54c-e,67],... 

Another synthetic method involves treating the parent aromatic hydrocarbon with sodium hypochlorite in water-chloroform, using phase transfer agents like tetrabutylammonium hydrogen sulfate or benzyltrimethylam-monium chloride.15 The epoxides are formed in high yields. The rate is pH dependent, and epoxide formation is most facile at pH 8-9. Many K-region arene oxides like 1,165, acenaphthylene 1,2-oxide (19), 1-azaphenanthrene 5,6-oxide (20), 4-azaphenanthrene 5,6-oxide (21), 1,10-phenanthroIine 5,6-oxide... 

Oxidation of internal perfluoroolefins by alkaline solutions of hydrogen peroxide and alkaline and alkaline-earth hypohalides leads to the formation of olefin oxides, the yield of the target product being 40-50%. The reaction with sodium hypochlorite in an alkali in the presence of acetonitrile is an example of epoxidation performed by the nucleophilic attack of the OC1-anion of the multiple bond with further elimination of the chloride anion by the intermediate carbanion (79IZY2509, 79IZV2812, 79RP666176,... 

Epoxidation of Butenolides with Sodium Hypochlorite Typical Procedure92 ... 

Other Applications. Other (/ ,/ )-stilbenediamine derivatives have been used to direct the stereochemical course of alkene dihydroxylation (with stoichiometric quantities of Osmium Tetroxide and epoxidation of simple alkenes with Sodium Hypochlorite and manganese(III) complexes. ... 

Naphthoquinone on reaction with sodium hypochlorite in dioxane affords the 2,3-epoxide in 71.5% yield. 

Further elaboration to the alkaloid involves epoxidation at the 5,6-double bond. This reaction is in keeping with the formation of 5,6-epoxybenzo[h]quinoline, m.p. 111-112°C, when the parent heterocycle is treated with sodium hypochlorite under phase transfer conditions (S. Krishnan, D.6. Kuhn and 6.A. Hamilton, J. Amer. chem. Soc., 1977, 99, 8121). 

E. Guilmet, B. Meunier, A new catalytic route for the epoxidation of styrene with sodium hypochlorite activated by transition metal complexes. Tetrahedron Lett. 21 (1980) 4449. 

Foucaud, A., and Bakouetila, M., Facile epoxidation of alumina-supported electrophilic alkenes and montmorillonite-supported electrophilic alkenes with sodium hypochlorite. Synthesis, 854, 1987. Duncan, G.D., Li, Z.-M., Khare, A.B., and McKenna, C.E., Oxiranylidene-2,2-Zt/5(phosphonate). Unambiguous synthesis, hydrolysis to l,2-dihydroxyethylidene-l,l-fcA(phosphonate), and identification as the primary product from mild Na2WO4/H2O2 oxidation of ethylidene-l,l-Z7/5(phosphonate), J. Org. Chem., 60, 7080, 1995. 

Jacobsen and co-workers have devised highly enan-tiospecific manganese complexes for epoxidations of olefins with sodium hypochlorite.94 Peracids and amine N-oxides can also be used as oxidants. A typical catalyst is shown in 10.43 ... 

Di-t-butyl-6-formylphenol has been employed as the manganese derivative shown with readily available trans-1,2-diaminocyclohexane, which can be easily resolved, for highly enantioselective epoxidation (for example of Z-1-phenylprop-1-ene) when employed in catalytic amounts with sodium hypochlorite solution as oxidant (ref.120). 

The syntheses of peifluorinated epoxides by oxidation of perfluorodUiydrofurans with sodium hypochlorite and Diels-Alder reaction of 2,5-dialkyl-3,4-bis(triiluor-omethyl)furan with hexafluoro-2-butyne should me mentioned among the reactions proceeding with participation of endocyclic C=C bonds. 

Excellent conversions and selectivities were observed both with respect to the alkene and the primary oxidant [62]. In nitro-Michael reaction it was noted that the Murphy s PTC does not work as a good chiral catalyst for the Michael reaction of chalcone, but the same PTC effectively catalyses the epoxidation of chalcones with sodium hypochlorite (NaOCl) [24c]. Trials for the epoxidation of chalcone in the combination of hydroperoxides and modified guanidines 19 [27b] resulted in less effective asymmetric induction compared to the Murphy s PTC [53] (Scheme 4.21). 

Epoxidation. Marmar epoxidized two ,j3-unsaturated ketones, benzalaceto-phenone and fraws-dibenzoylethylene, in yields of >90%, by using ordinary commercial hypochlorite bleach (Clorox) in pyridine solution. 1,4-Naphthoquinone is also epoxidized in 71.5%, yield with sodium hypochlorite in dioxane. In this case addition of pyridine results in further oxidation. 

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