Oxone epoxidation with

Oxone, K2C03 Shi s asymmetric epoxidation with ketone 1. 

To mimic the square-pyramidal coordination of iron bleomycin, a series of iron (Il)complexes with pyridine-containing macrocycles 4 was synthesized and used for the epoxidation of alkenes with H2O2 (Scheme 4) [35]. These macrocycles bear an aminopropyl pendant arm and in presence of poorly coordinating acids like triflic acid a reversible dissociation of the arm is possible and the catalytic active species is formed. These complexes perform well in alkene epoxidations (66-89% yield with 90-98% selectivity in 5 min at room temperature). Furthermore, recyclable terpyridines 5 lead to highly active Fe -complexes, which show good to excellent results (up to 96% yield) for the epoxidation with oxone at room temperature (Scheme 4) [36]. 

Recently, oxaziridinium salts derived in situ from chiral iminium salts (1 and 2) and Oxone were found to catalyze epoxidation with moderate-to-good enantioselectivity (up to 73% ee) (Scheme 6B.4) [6], Although the substrates are limited to conjugated olefins, this reaction has an advantage in being catalytic with respect to chiral iminium salts. 

Potassium 1-alkenyltrifluoroborates permitted alkene epoxidation with oxone or m-CPBA with excellent conversions without cleavage of the G-B bond (Equation (77)).448... 

A number of new oxaziridinium epoxidation reagents have been reported. A new axially chiral epoxidation catalyst 4 has been reported <070BC501>. These catalysts, as are others, are converted to an oxaziridinium with Oxone, which then epoxidizes the olefin. This study examined several chiral groups on the nitrogen as well as both atropisomers. The (S,F)-isomer 4 provided the (1R,2R) epoxide with moderate enantioselectivity and 82% conversion. The (.V,A/)-isomcr of 4 provided the (lS,2S)-epoxide in slightly lower enantiomeric excess (76%) and lower conversion as well. 

In the Shi epoxidation, an oxone (potassium persulfate, KOSO2OOH) in the presence of a fructose-derived catalyst, 7.57, generates epoxides with high enantiomeric excess oxone is best used to oxidize aldehydes to carboxylic acids in the presence of DMF. 

Denmark and Wu used 0-labeled ketone 81 in their studies of epoxidation of 1-phenylcyclohexene, yielding the conclusion that dioxiranes are the reactive oxidants in monophasic epoxidations with Oxone <1997JOC8964>. 

An indirect method for generating an amino alcohol (124) is to open an epoxide with azide to give the azido-alcohol 123, and subsequent reduction (19-50) gives the amine group.Sodium azide and Oxone react with epoxides to give an azi-do-alcohol. Under Mitsunobu conditions (10-17), epoxides are converted to 1,2-diazides with The reaction of trimethylsilyl azide and an epoxide was... 

As shown in the Table, with 5 mol% of 1,1-dioxotetrahydrothiopyran-4-one as catalyst,10 epoxidation of various olefins (2-mmol scale) in a homogeneous acetonitrile-water solvent system with 1.5 equiv of Oxone at room temperature can be achieved in a short period of time with excellent yields of epoxides (80-97%) isolated by flash column chromatography.2 As the pH of the reaction is maintained at 7-7.5 by sodium bicarbonate, acid- or base-labile epoxides (entries 12-14) can be easily isolated without decomposition. More importantly, the in situ epoxidation of olefins can be performed on a large scale directly with 5 mol% of tetrahydrothiopyran-4-one, which is oxidized immediately by Oxone to 1,1-dioxotetrahydrothiopyran-4-one during the epoxidation reactions. For example, with 5 mol% of tetrahydrothlopyran-4-one, substrates 3,5 (20 mmol each) and 11 (100 mmol) were epoxidized with excellent isolated yields of epoxides (91-96%). 

Recent work with main group catalysts has concentrated on the use of Oxone (potassium peroxymonosulfate) as co-oxidant with organic ketone derivatives. Shing et al. have described an arabinose ketone catalyst containing a tuneable butanediacetal functionality (Fig. 1.2e) which can be used for asymmetric epoxidation with up to 90% ee [198]. The group of Shi reports on a range of ketones bearing... 

Scheme 23 (a) The Tp Cu-catalyzed styrene epoxidation with oxone. (b) The catalytic... 

Scheme 14 Epoxidation with oxone and a supported Cu catalyst...

An epoxidizing agent that has found widespread use is dimethyl dioxirane (DMDO). The reagent is generated from acetone and Oxone , a source of potassium peroxomonosulfate (KHSO5) (5.50). Epoxidation with DMDO occurs under mild, neutral conditions, without any nucleophilic component, which is ideal for preparing sensitive epoxides. For example, the enol ether 41 was epoxidized selectively using DMDO (5.51). ... 

Progress continues to be made in the area of novel asymmetric methods. For example, the [l,4]diazepanone 16 has been shown to promote asymmetric epoxidation with modest enantioselectivities in the presence of Oxone and a mild base. The active oxygen transfer species is believed to be the chiral dioxiranc 17, which adopts a twisted conformation and imposes a facial bias via the phenylsulfonyl groups. Yields are relatively low (< 50%), presumably due to Baeyer-Villiger degradation of the chiral auxiliary (16 18). This... 

An in situ method for epoxidations with dimethyldioxirane using buffered aqueous acetone solutions of Oxone has been widely applied.The epoxidation of 1-dodecene is particularly impressive in view of the difficulty generally encountered in the epoxidation of relatively unreactive terminal alkenes (eq 7). A biphasic procedure using benzene as a cosolvent and a phase-transfer... 

Oxone and its derivatives have also been used with chiral iminium salts and amines to formenantiomerically enriched epoxides. The scope and enantioselectivity of epoxidation with chiral iminium salts with Oxone and PI14PHSO5 have made progress during recent years. Chiral iminium salts (7 and 8) have been particularly successful for various olefins (eqs 40 and 41). ... 

The epoxidation with in situ generated dioxiranes often requires careful control of the reaction pH. Since Oxone rapidly autodecomposes at high pH, early epoxidations were usually carried out at pH 7-8. In contrast, higher pH was found to be beneficial to epoxidation with ketone 2. For example, conversion of /ra 5-P-methylstyrene 11 to its epoxide 12 increased from 5% at pH 7-8 to > 80% at pH > 10 while a high enantioselectivity (90-92% ee) was retained. Analysis of the reaction cycle implied that a Baeyer-Villiger oxidation from intermediate 8 could be one of the possible decomposition pathways for ketone 2. A higher pH would facilitate the formation of anion 9 and subsequent formation of dioxirane 10, thus... 

While Oxone has been commonly used to generate dioxiranes from ketones, Shi s studies have shown that epoxidation with ketone 2 or 5c can be carried out with a nitrile and H2O2 as the primary oxidant, giving high enantioselectivity for a variety of olefins. Peroxyimidic acid 55 is likely to be the active oxidant that reacts with the ketone to form dioxirane 10. Mixed solvents, such as CH3CN-EtOH-CH2Cl2, improve the conversions for substrates with poor solubilities. This epoxidation system is mild and provides conversion and enantioselectivity similar to that using Oxone as oxidant. 

Dioxiranes for alkene epoxidation may be prepared in situ from a catalytic amount of a ketone and Oxone (potassium peroxymonosulfate triple salt). )V,)V-Dimethyl-and A, A -dibenzylalloxans (20a) and (20b) (Figure 3) have been prepared and used as novel dioxirane catalysts for the epoxidation of a range of di- and tri-substituted alkenes in good to excellent yield. H2O2 (rather than the usual Oxone) has been successfully used as primary oxidant in asymmetric epoxidations with Shi s fructose-derived ketone (21) in acetonitrile. The ketone is converted into the dioxirane, which is responsible for epoxidation and the active oxidant responsible for dioxirane formation is proposed to be peroxyimidic acid formed by combination of H2O2 with acetonitrile. ... 

The synthetic route of sulfite-linked cycloaliphatic epoxy resin is presented in Figure 8.13 [38]. The synthesis of intermediate is achieved via the nucleophilic substitution reaction of thionyl chloride with cyclohex-3-enyl-1-methanol. Subsequently, Epo-S is obtained by epoxidation with OXONE oxidant. Epo-S is liquid at room temperature which is favorable for the underfilling encapsulation for high-density electronic packaging technologies such as flip chip plastic ball grid array (FC-PBGA) and MCM. 

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