Oxidation with Alkaline Hydrogen Peroxide

This method was first described by Weitz and Scheffer. The oxidation begins with a reversible attack by the nucleophilic hydroperoxy anion on the conjugated system, and an oxirane conjugated with an electron-attracting group is formed by ring-closure following the loss of OH from the intermediate enolate anion (Eq. 15). 

The reaction is generally not stereospecific. One of the causes of this is the lifetime of the intermediate enolate ion, which is usually long enough for rotation to occur around the Ca-CP bond, but polar and steric effects also influence the stereo- 

For steric reason, alkaline hydrogen peroxide yields only the /rans-oxirane from cis- or trans-42 (Eq. 16).  

Mono- and polyepoxyalcohols have been prepared from phorone in very stereoselective syntheses. The trans-oxirane 43 is formed from indenedione by participation of the C-1 carbonyl group.  

The polar interaction of a distant substituent has been observed in the reaction of 44. If R = = H, the j3-oxirane is formed, while if there is a carbonyl group on 

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Double bonds in a,/3-unsaturated keto steroids can be selectively oxidized with alkaline hydrogen peroxide to yield epoxy ketones. In contrast to the electrophilic addition mechanism of peracids, the mechanism of alkaline epoxidation involves nucleophilic attack of hydroperoxide ion on the con-... 

All gaseous sulfur products obtained as a result of incubation of sulfur-treated fruit were oxidized with alkaline hydrogen peroxide, precipitated as barium sulfate, and counted with a thin window Geiger counter. The peel and peel proteins were oxidized with magnesium nitrate, the sulfur was precipitated as barium sulfate according to standard methods, and counted as in the case of the gaseous products. Counting data, as reported, are fully corrected. 

Reaction of an (S, S )-diol (a/ )-0 -chloro boronic ester 4 with a Grignard or lithium reagent leads to an intermediate borale complex30 5 which rearranges to a secondary alkyl boronic ester 6. One use of the secondary alkyl boronic ester 6 is oxidation with alkaline hydrogen peroxide, which is known to proceed with retention of configuration31, to form the corresponding chiral secondary alcohol. 

The base-induced reaction of dichloromethyl methyl ether with trialkyl- and triarylboranes also provides a powerful method for the preparation of the corresponding tertiary carbinols.1617 fn this case, all three groups transfer readily from horon to carbon under mild conditions, and oxidation with alkaline hydrogen peroxide provides the tertiary alcohol ... 

The most frequently reported oxidation reaction of isatins is the oxidation with alkaline hydrogen peroxide to give anthranilic acids. This procedure has been both as a proof of structure of isatins and as a method of synthesis of anthranilic acids. The oxidation has been applied to alkyl 8"10 11 23 33>38-40>46 49>50>118halo n.18.35.36-38-40.47.10 .11 . 119,136,240 alkoxy,26,a8 39,47,75.io7,ii8,i36 trifluoromethyl,33,38,137 and nitro8,120,217 isatins. Use of N-substituted isatins led to N-substituted anthranilic acids.66,71,125,158,169,243 In the oxidation of 5-bromo-l-(y-carbethoxypropyl)-7-ethylisatin, 60 was isolated after treatment with ethanol and acid.11 Oxidation of isatin derivatives 61 led, after treatment with diazomethane, to the acridine derivatives 62.67 Application of this oxidation method to 7-hydroxyisatins gave rise to benzoxazo-lones (63).2,41... 

Similarly, Hoffman7 6 recently reported treatment of a-methyl-etyreae oxide with alkaline hydrogen peroxide to give an almost quantitative yield of acetophenone. It was suggested that attack by OOH ion is responsible for this phenomenon, which may be depicted as shown in Eq. (1304). 

The byproduct one obtains upon acidification is oxalic acid. Based on this, which bond must be cleaved during oxidation with alkaline hydrogen peroxide ... 

Boronatc 6 is oxidized with alkaline hydrogen peroxide to alcohol 24. The corresponding mesylate is reduced with lithium aluminum hydride to a methyl group. 

The paper also reports a new method for conversion of —SnX(CH3)2 into an hydroxyl group with the same configuration by oxidation with alkaline hydrogen peroxide in THF/CH3OH. 

Further oxidation of the A-oxide with alkaline hydrogen peroxide gives 6-hydroxyphenanthridine-5-oxide.353... 

The dialkenylchloroboranes undergo the usual reactions of vinylic boranes, e.g., protonolysis with acetic acid gives olefins, oxidation with alkaline hydrogen peroxide provides the corresponding carbonyl compounds. However, the most useful reactions of these compounds are their ready conversion to the stereochemically pure (E, Z)-1,3-dienes by the Zweifel reaction with I2-NaOH 37>107.108> and into the symmetrical (E,E)- 1,3-dienes, 09 0), mono-olefins 1U) and 1,4-dienes (Chart 10). 

Hydroboration of alkene 22 was realized49 by treatment with a large excess of diborane in anhydrous tetrahydrofuran, followed by oxidation with alkaline hydrogen peroxide. This procedure resulted in the formation of 3-deoxy-3-C-(hydroxymethyl)-l,2 5,6-di-0-iso-... 

Peracid oxidation of organylboranes is a smooth and operationally simple procedure that proceeds in mildly acidic conditions in atihydrous solvents. Yields are generally high and the method, though infre-quentiy used at present, should always be considered as an alternative to oxidation with alkaline hydrogen peroxide. 

Epoxidation of (+)-Piperitenone Oxide with Alkaline Hydrogen Peroxide Typical Procedure34 ... 

Synthesis of secootkiry eokois from l-aOtynes. Dihydroboration at room temperature of a terminal alkyne with either (I) or 9-BBN gives a 1,1-diborylalkane (3) this is treated at 0-5° with I eq. of methyllithium in ether. The product (4) rearranges to (S). An alkyl halide (100 excess) is then added, and the resultant secondary organo-borane (6) is oxidized with alkaline hydrogen peroxide. Secondary alcohols (7) are obtained in 70-85% yield. 

Reaction with trialkylboranes. Lane and Brown in 1971 reported a simple procedure for synthesis of highly substituted alcohols from trialkylboranes. For example, bromination of triethylboranc (1) under irradiation in the presence of water followed by oxidation with alkaline hydrogen peroxide gives 3-methyl-3-pentanol (2) in 88% yield. The reaction involves as the first step free-radical bromination in the a-position... 

Phenob. Organomcrcury halides of the type ArHgX react with diborane in THF under normal hydroboration procedures to give intermediate organoboranes which are not isolated but oxidized with alkaline hydrogen peroxide to give phenols in good yield. 

I lydroboration of I-methylcyclopentene (1) with diborane gives tris-(frans-2-melhyl-cyclopentyl)borane (2), which on oxidation gives rran.t-2-mcthylcyclopentanol (3). Addition of sodium cyanide to a solution of (2), followed by treatment with trifluoro-acetic anhydride (TFAA) and then by oxidation with alkaline hydrogen peroxide, gives... 

The most frequently reported oxidation reaction of isatins is the oxidation with alkaline hydrogen peroxide to give anthranilic acids. This procedure has been both as a proof of structure of isatins and as a method of synthesis of anthranilic acids. The oxidation has been applied to alkyl b.33,38-40,48,49,so,11,18,35,36,33-40,47,106,118, 119,136,240 25,38,39,47,75,107,118,136 trifluoromethyl, and... 

Borane, which is used as a complex with tetrahydrofuran [992] or dimethyl sulfide [611, 992] or generated in situ from lithium borohydride with boron trifluoride etherate [646] or sodium borohydride with aluminum chloride [184], reacts with 3 mol of an alkene to form a tertiary borane. The oxidation with alkaline hydrogen peroxide [183, 992, 1201] or with trimethylamine oxide [991, 992] yields an alcohol (equations 598 and 599). 

Several (catechol)cyclopropylboranes have been synthesized stereoselectively in good yields by reacting 1,1-dibromocyclopropanes first with butyllithium and subsequently with catechol-borane. Only (2,2-dimethylcyclopropyl)catecholborane (1) has been isolated in 91 /o yield, from l,l-dibromo-2,2-dimethylcyclopropane, prior to oxidation with alkaline hydrogen peroxide (see Section 5.2.1.2.3.). 

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